Mina Karimi; Abolghasem Sadeghi Niaraki; Ali Hosseininaveh Ahmadabdian
Abstract
Extended Abstract Introduction Underground infrastructure such as electricity, gas, telecommunications, water and sewage are managed by different organizations. Since most projects in these organizations require drilling,and imprecise excavations will endanger infrastructure and result in extensive financial ...
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Extended Abstract Introduction Underground infrastructure such as electricity, gas, telecommunications, water and sewage are managed by different organizations. Since most projects in these organizations require drilling,and imprecise excavations will endanger infrastructure and result in extensive financial and physical losses, drilling projects require having accurate information about the infrastructure status. However, reaching accurate position of facilities such as pipes and cables is difficult due to their being concealed underground.Nowadays, ubiquitous computing and new developments in Geospatial Information Systems (GIS) can be an appropriate solution to such problems. This new generation of GIS is called the Ubiquitous Geospatial Information System (UBGIS). New technologies such as Augmented Reality (AR) can visualize this infrastructure on platforms like smart phones or tablets. Such technologies show spatial and descriptive attributes of these utilities more interactively, and thus can be applied as a modern solution for this problem. One of the major features of AR is identifying and locating real-world objects with respect to the person’s head or a camera. To have an accurate Augmented Reality, the position and orientation (pose) of the camera should be estimated with high accuracy. Therefore, exterior orientation parameters of the camera are required for AR and tracking. Different methods are used to calculate these exterior orientation parameters. One of the most common methods applies different sensors,such as Global Positioning System (GPS) and Inertial Measuring Unit (IMU),embedded in smart phones or tablets to calculate these parameters. These sensors include accelerometers, gyroscopes, magnetic sensors and compasses. Althoughsimple and fast, this method is not suitable for accurate cases, because sensors of mobile phones or tabletscannot provide such high accuracy. Vision-based (sometimes called image-based) method is another way of estimating exterior orientation parameters. In this method, fixed or dynamic images are used to determine the position and orientation of camera. The method is more complex and slower, but more accurate than the first one. Materials and Methods Regarding previously mentioned issues, the present article aims to visualize underground infrastructure using both sensor-based and vision-based approaches of Augmented Reality. Since the sensors embedded in a mobile phone or tablet do not provide such an accuracy (an accuracy of a few centimeters considering diameter of pipes and width of streets and pavements), a novel vision-based approach is proposed. In this method, image-based techniques and special kinds of targets, known as coded targets, are used to estimate camera’s position and orientation along with space resection method. In photogrammetry,space resection involves determining the spatial position and orientation of an image based on thesize of ground control points appearing on the image. Since space resection is a nonlinear problem, existing methods involve linearization of the collinearity condition and the use of an iterative process to determine the final solution using the least squares method. The process also requires determination of the initial approximate values of the unknown parameters, some of which must be estimated using another least squares solution. In order to obtain suitable initial values for space resection procedure, data received from GPS, accelerometers, and magnetic sensors are used and a low-pass filter is applied to reduce noise and increase precision. Then, due to improved camera pose parameters, the resulting virtual model is overlaid at its correct real worldplanimetriclocation. The planimetric coordinates are shown graphically on the ground and the Z coordinate (depth) is presented as a descriptive parameter. Results and Discussion Both proposed methods were implemented and tested in an Android Operating System. Camera pose parameters were estimated and the virtual modelwas overlaid at its correct real world planimetric location and shown on camera. Then, the results were compared and evaluatedusingthe well-known photogrammetry software, Agisoft, with the aim of modelling and precise measuring based on basic photogrammetry and machine vision. For sensor-based method, mean accuracy of the position parameters equals 4.2908±3.951 meters and mean accuracy of orientation parameters equals 6.1796±1.478 degrees,whilein vision-based method,these decreases to 0.1227±0.325 meters and 2.2017±0.536 degrees, respectively. Thus, results indicate that the proposed methodimprove accuracy and efficiency of AR technologies. Conclusion Augmented Reality is a technology that can be used to visualize underground facilities. Although,processing in sensor-based methods is sufficiently fast and simple, they lack the precision required for this purpose. Despite the fact that noise elimination and sensor integration using Kalman filter improves accuracy to some degree, it still does not reach the required accuracy. The present article sought to improve the accuracy of augmented reality in underground infrastructureusing targets. Results indicated that the machine vision and vision-based methods improve the accuracy. In drillings, third dimension (accuracy of height measurements) is as crucial as other parameters, thusit is suggested that future researches consider this not as a descriptive parameter, but as a three dimensional parameter to reach 3dimensional visualization.
Extraction, processing, production and display of geographic data
Hamid Ganjaeian; Fatemeh Menbari; Afshan Ghasemi; Mozhgan Nosrati
Abstract
Extended AbstractIntroductionSubsidence risk, unlike many risks such as floods and earthquakes, is insignificant and in the long run causes a lot of damage such as cracking of buildings, sloping of high facilities, destruction of agricultural lands, subsidence, etc. So the areas at risk are facing a ...
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Extended AbstractIntroductionSubsidence risk, unlike many risks such as floods and earthquakes, is insignificant and in the long run causes a lot of damage such as cracking of buildings, sloping of high facilities, destruction of agricultural lands, subsidence, etc. So the areas at risk are facing a lot of challenges. Among the areas that are at risk of subsidence are the plains of arid and semi-arid regions, including the plains of Iran. In fact, the location of a large part of Iran in the arid and semi-arid region has caused these areas to face a shortage of surface water resources, and this has led to overuse of groundwater resources in recent years and the occurrence of the risk has subsided. One of the areas that is at risk of subsidence is Kaboudar Ahang-Famenin plain in Hamadan province. Due to the lack of limiting geomorphological barriers, this plain has been associated with the development of many agricultural lands and due to the lack of sufficient surface water resources, the utilization of groundwater resources in this plain has been more than allowed and this has caused a decline. Extreme groundwater resources in this area and eventually the risk of subsidence. Due to the importance of the issue, in this study, the subsidence of Kaboudar Ahang-Famenin plain has been evaluated and the effective factors in its occurrence have been analyzed. Materials and methodsIn this study, in accordance with the subject and objectives, statistical information (information about 13 piezometric wells in the study area), library and video (radar images related to Sentinel 1 satellite, Landsat satellite images and also 30 m high digital model SRTM) has been used as research data. The tools used in the research include GMT software (to prepare subsidence mapping using radar interference and Russian SBAS time series method), Google Earth (to monitor area and identify subsidence) and ArcGIS (to prepare final maps). According to the objectives, this research has been done in three stages. In the first stage, using the digital model of 30 m altitude SRTM and Landsat satellite images, the geomorphological status and land use of the region have been studied. In the second stage, in the second stage, using information related to 13 piezometric wells, the groundwater depletion situation of the region was investigated and in the third stage, using Sentinel 1 radar images and SBAS time series method, the amount was evaluated. Subsidence of Kaboudar Ahang-Famenin plain has been studied. Discussion and resultsThe study of the altitude situation of the region shows that there is a very small difference in height between the cities of Kaboudar Ahang and Famenin and also there are no significant obstacles and landforms in this distance. Also, the study of the slope classes of the region shows that the area of Kaboudar Ahang-Famenin plain is less than 10% in the slope class and the region does not have steep and restrictive areas. According to the prepared maps, Kaboudar Ahang-Famenin plain, in terms of geomorphology, has no limiting obstacles for the development of agricultural lands as well as residential areas. In fact, the lack of restrictive barriers has led to the development of agricultural lands in this region, especially irrigated agricultural lands in recent years, and this has led to excessive pressure on groundwater resources in recent years. The results of the study of the decline in groundwater resources in the region indicate that the rate of decline in water levels during a period of 24 years has been between 14.7 (Hemehkasi well) to 78.1 (Einabad well) meters. Also, according to the calculations, most of the studied wells have faced an average of more than 2 meters of water level drop annually. Also, the results of the assessment of subsidence in the region indicate that the study area has had a subsidence of 29 to 216 mm during a period of 5 years (from 16/01/2015 to 14/01/2020). ConclusionThe results of studying the natural state of Kaboudar Ahang-Famenin plain have shown that this plain has a high subsidence potential due to its geomorphological and hydro-climatic conditions. In fact, in terms of geomorphological status, this plain is without limiting obstacles for the development of agricultural lands, and this issue has led to the development of irrigated agricultural lands regardless of environmental capabilities, including the hydro-climatic situation of the region. According to the above cases, the development of agricultural lands, regardless of the capacity of water resources in the region, has led to over-harvesting of groundwater resources and as a result, a sharp drop in groundwater levels Based on the results of the evaluation of 13 wells studied, most of the studied wells, with an average annual water level drop of more than 2 meters and this issue has caused the Kaboudar Ahang-Famenin plain during The 5-year period (from 16/01/2015 to 14/01/2020) should have a subsidence of 29 to 216 mm. Also, the results of the study of the spatial distribution of subsidence have shown that the highest amount of subsidence is related to the middle areas of the region and the distance between Kaboudar Ahang and Famenin cities, and considering that in these areas there was the highest level of groundwater loss, Therefore, it can be said that the main cause of subsidence in the region has been a sharp decline in groundwater resources. The sum of the results of this study has shown that Kaboudar Ahang-Famenin plain is in danger of subsidence and this issue has led to the emergence of numerous depressions in this plain which is a serious threat to human facilities and habitat.
Hooshang Seifi; Ismail Gorbani
Abstract
Introduction Presently, population growth, urban development, the importance of agriculture in economic development, the need for supplying water demands of this sector and improving public health have multiplied water consumption as compared to the past. For appropriate and optimal use of water resources, ...
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Introduction Presently, population growth, urban development, the importance of agriculture in economic development, the need for supplying water demands of this sector and improving public health have multiplied water consumption as compared to the past. For appropriate and optimal use of water resources, it is necessary to know the amount of available water in the area, its temporal and spatial changes, and the exact planning for maintenance and utilization of the available water. Accordingly, studying and measuring changes in snow levels, as an important source of water in mountainous areas, is very important. Snow cover is one of the important parameters involved in the amount of snowmelt. Due to the difficulty of monitoring and measuring snow cover level in mountainous basins, satellite images are used as alternatives to monitoring and ground operations in the preparation process of snow cover map. In this regard, the use of satellite imagery and remote sensing, due to low cost, up-to-date and extensive coverage, is a major breakthrough which can be used to identify snowy areas and evaluate changes in that method. Detailed analysis of snow-related issues requires a set of snow measurements and observations. OLI and TIRS sensors with various advantages like appropriate number of bands, referable spatial resolution, and sequential time series are considered to be an appropriate tool for this purpose. The main objective of this research is to estimate snow coverage of Sahand Mountain using satellite images received from OLI and TIRS sensors and by object-oriented classification method. Materials and Methods The present study use images received from OLI and TIRS sensors, and Landsat 8 satellite on 08/02/2017 (Pass and Row no. 34-168), as well as Digital Elevation Model based on data received from Aster Sensor and Terra satellite with a resolution of 28.5 meters to produce snow coverage map. Geo TIFF satellite data were originally requested from the American Geological organization and received from USGS site. Envi 5.3, eCognition 9.1, and ArcMap 10.4.1 software were used for processing and preparation of images, as well as classification and extraction of the final maps. In order to classify and extract snow cover surface with high precision, NDSI, NDVI, LST, and Brightness algorithms were used along with fuzzy algorithms. Results and Discussion Classification of satellite digital images is one of the most important methods for extracting applied information, which is currently performed by two general methods of pixel-based processing and object-based processing. The former method is based on the classification of numerical values of images, and the latter use not only numerical values, but also content, texture, and background information in the image classification process. Recent researches have processed image pixels and have only applied NDSI algorithm to estimate snow cover level. Therefore, pixels recognized as snow in such researches may contain snow cover and other land uses, which reduces the precision of snow cover extraction and makes the process of extracting all snow covers difficult. Extraction of snow cover using MODIS images is one of such researches. Due to low spatial resolution of these satellite imageries, extraction of mountainous valleys snow cover, as well as the separation of snow cover from the cloud cover is done with very low accuracy. Therefore, due to higher accuracy of object-oriented classification as compared to pixel-based classification, object-based techniques were used to classify and estimate snow cover. In object-oriented method, pixels are classified based on shape, texture and gray tone of the image. Thereby, pixels change into image objects and resolves the pixel blend problem. Therefore, by assigning each object to a specific land use, classification accuracy increases. Also, using complementary algorithms such as Brightness and NDVI along with the NDSI algorithm will improve the accuracy of findings as compared to other recent research. Therefore, using Landsat 8 satellite images and the new method of image classification, the present study extract snow cover from different domains of the study area. The snow cover in valleys was also extracted with appropriate and acceptable accuracy using different algorithms. Using LST algorithm in object-oriented processing method, detecting and separating snow cover from cloud cover was made possible. In this way, a satisfactory result was obtained from the snow cover. Finally, snow cover for Sahand Mountain Range was calculated to be 1882.88 km2. The results can be used as an alternative to snow measurement stations. Conclusion Based on research findings, using Landsat 8 satellite imagery and object-oriented processing methods for image classification have the necessary efficiency in extracting snow cover in mountainous regions. Given the precise estimation of the snow surface and the low cost of using this type of satellite imagery, it is possible to use this type of images and check the snow cover with great confidence. While ground observations are expensive due to impassibility of mountainous regions, and also they are not sufficiently precise.
Extraction, processing, production and display of geographic data
Mohammadhasan KorkiNezhad; Aliakbar Shamsipour; Kyoumars Habibi
Abstract
Extended AbstractIntroductionCity is a living, dynamic being evolving over time in the context of physical and anthropogenic components and complex relationships between them. It is the reflection of the role and attitude of man-kind influenced by social, economic, political, cultural and geographical ...
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Extended AbstractIntroductionCity is a living, dynamic being evolving over time in the context of physical and anthropogenic components and complex relationships between them. It is the reflection of the role and attitude of man-kind influenced by social, economic, political, cultural and geographical factors and conditions. Increased population and density in urban areas have far-reaching consequences, such as increased consumption of natural resources, land-use changes, climate change, and disruptions in the exchange of material and energy. Consequently, cities face many issues and problems, the most important of which are issues related to urban design. These include poor ventilation, high heat load, air pollution caused by the physical characteristics of cities, and insufficient attention to the capabilities, natural characteristics and climate of the region and the city.Data and MethodsThe present study seeks to prepare an urban climate analysis map to study and analyze spatial and climatic information collected from Tehran. Urban Climate Map (UCMap) is an information-based and analytical tool that combines factors of urban climate with urban planning factors and some environmental conditions to provide an image of urban climate issues in a two-dimensional environment. Urban climate map consists of an urban climate analysis maps (UCAnMap) and an urban climate recommendation map (UCReMap). Urban climate analysis maps apply various spatial information layers of heat load maps such as building volume, urban topography and green space along with layers of land cover, natural landscape, and proximity to open spaces in dynamic capacity maps. The proposed model is generally based on the evaluation and analysis of variables affecting climatic conditions. Based on six layers of building volume, land cover, topography, proximity to open spaces, green space, and natural landscape, maps were prepared in Arc/GIS10.4.1 environment for Tehran urban area. To eliminate the unit and reach comparability and overlap, the layers were standardized and used to prepare maps of ambient heat load and dynamic capacity.Results and DiscussionThree layers of building volume, topography, and green space were weighted and combined to create a heat load map. The other three layers of land cover, natural landscape, and proximity to open spaces were also combined to create a dynamic capacity map. Afterwards, these two maps were combined to create an UCAnMap. The resulting map was close to the on the ground realities. For example, building volume has a negative effect and increases heat load in urban areas. On the other hands, green space reduces heat load and has a positive effect. The central and southwestern parts of the city have a high heat load and core areas of the urban heat island have been calculated and obtained in these areas. The resulting map was classified into 8 categories to create urban climate analysis map of Tehran.ConclusionResults indicated that 59% of the urban area in Tehran, mostly located in the northern part of the city, has a good cooling and ventilation condition while 19% of the study area, mainly in the central, southern, and southwestern parts, faces heat stress and lacks an appropriate air ventilation condition. 22% of the study area, scattered all over the city but mostly located in the northern, western and eastern parts, faces an intermediate condition. According to the calculated heat load map, the central, southern, and western parts (in region 21) of the study area face a high and unfavorable ambient heat load. And many parts of the 4th, 1st, 2nd, 5th, and 22nd urban districts are characterized with low ambient heat load and favorable climatic conditions.
Sohrab Asgari
Volume 22, Issue 85 , May 2013, , Pages 79-96
Abstract
Managing a country is one of the most important issues in the world. This aim will achieve through evealuated and scientific planning processes. Good fulfillment of the plans will cause positive results. In Iran, palnning and territory management has a long history. In contemporary era, planning was ...
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Managing a country is one of the most important issues in the world. This aim will achieve through evealuated and scientific planning processes. Good fulfillment of the plans will cause positive results. In Iran, palnning and territory management has a long history. In contemporary era, planning was an organization agenda from the Qajar period,. In Reza shah's kingdom planning was an important issue General information office and Statistics Bureau were the first offices founded. Applying regional planning approach was the first steps in governmental economic programs, 5 years planning policy was applied in the Pahlavi period. The Islamic revolution metamorphosed all former political and social structures. Because of Mismanaging of main affaires in the country, many devastating crises appeared. One of the mismanaging was encouraging population increase. Some sensitive laws were ratified and as a result, a migration trend in a vast shape emptied many villages and caused slum and shanty town. Imposed war and international embargoes were 2 samples of big crisis which accelerated migrations. To face job cuts, and also to produce more strategic crops, idea for cultivating in pasture lands and grass lands was approved, This was a formal aggression forests and pasture lands bases. This aggression caused soil erosion in the country and millions tons of soil erode and destroy completely. Deforestation is the main cause of floods in recent years. In other sides mismanaging has caused environmental disasters around the country. The main issue of this article is evaluating of political decision impacts in geographical space organizating from environmental viewpoint in the country in recent decades.
Extraction, processing, production and display of geographic data
Shokoufeh Farhadi; Nazila Mohammadi; Amin Sedaghat
Abstract
Extended AbstractIntroductionReconstruction of 3D models and their use in photogrammetry and remote sensing has been considered as the most important and challenging topics in recent years. With the development of laser scanner technology and obtaining spatial data of the environment and objects, the ...
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Extended AbstractIntroductionReconstruction of 3D models and their use in photogrammetry and remote sensing has been considered as the most important and challenging topics in recent years. With the development of laser scanner technology and obtaining spatial data of the environment and objects, the use of this technology has increased nowadays. This technology extracts points from the external surfaces of the environment or objects in high volume, in a short time, which is called point cloud.Due to laser scanners’ easy placement, point clouds are usually taken from different angles, so they define in the different coordinate systems, which must be unified to give a complete 3d view of the object. The process is considered as “registration”.For this purpose, first, the corresponding pairs of points in each point cloud must be determined and then they must be matched correctly.after all a three-dimensional model is created.Finding the best pair of corresponding points in the Point clouds as well as estimating the optimal error metric and the displacement between pairs of corresponding points is one of the most important and challenging steps of three-dimensional reconstruction.Three-dimensional descriptors are one of the most suitable tools for determining the corresponding pairs of points in Point cloud. These descriptors create a set of information for every single point to determine the corresponding points in each Point cloud. Defining a three-dimensional descriptor whose computation complexity is low but its descriptive is high, can help to find the correct pair of points for 3d registration and modeling.Materials & Methods The main purpose of the present study is to define a strong three-dimensional descriptor to find the best corresponding pair of points to reconstruct the three-dimensional model.The descriptor proposed in this study consists of two single local three-dimensional descriptors based on the spatial and geometric properties of the Point cloud, which combine to form a strong descriptor to determine corresponding points in the Point cloud.Laser scanners extract a large volume of points from surfaces in a short period of time, which due to the reflection of laser beams, Point cloud may contain noise and mistakes. In the process of analyzing and using the data, these mistakes cause problems and should be removed in the pre-processing phase. To define the desired descriptor, in the pre-processing phase the Point cloud gets ready to extract the required properties.The Statistical removal filter method is used to remove the noise and the voxel grid filter method is used to improve the speed of future preprocessing.Each point in the neighborhood of Query Point provides a lot of that can be used to create the desired descriptor.In the present study, by determining the appropriate neighborhood radius and Nearest Neighbor Search (NNS) method, using the k-dimensional tree, correct and efficient neighborhoods are determined for each point.In the first step, a spatial descriptor is formed for each point. This descriptor is defined in the form of a histogram based on two distances for the point in its neighborhood. In the second step, the angles of the normal vectors of the Point cloud in different states are used to create a descriptor based on geometric information. In this research, two features called and have been used, which for each descriptor is formed in the form of a histogram. Then the spatial descriptor is combined with each of the descriptors based on the geometric feature and forms two desired descriptors.To ensure the accuracy of the matching process based on the proposed descriptor, by assigning a suitable threshold for the basis of the distance between the Query point and its neighborhood, with the corresponding point of the Query point and its neighborhood in the second Point Cloud, incorrect correspondences are detected and removed. Next, the remained correct corresponding pairs of points are used to reconstruct the three-dimensional model.Results & DiscussionIn this research, two sets of Point cloud have been used to evaluate the proposed process. These two data sets are obtained in such a way that in the first data set the perspective and angle of view and in the second data set the position and arrangement of objects are changed.By forming descriptors based on spatial and geometric features in different neighborhood radii and then forming a proposed combination descriptor based on what has been mentioned, it can be considered that combining the geometric descriptors with spatial descriptors, in cases where The two datasets have less relative overlap or more relative rotation than each other, in contrast to the position shift, leading to improved descriptor performance and increased matching accuracy.Considering the results obtained from the comparison of the proposed descriptors, it can be said that because of the existence of two different radii in each part of descriptors based on spatial and geometric relations in the proposed descriptors, it turns out that the required descriptor is high quality.On the other hand, the properties used in these descriptors are also resistant to changing the position of objects and have high efficiency in mentioned category. Also, the process of identifying and eliminating incorrect correspondences improves the matching process and increases the matching percentage of similar points up to 25% in the study data set.ConclusionThe results of comparing the set of Point Cloud studied using the proposed descriptor indicate that this descriptor is more efficient in cases where two data sets rotate relative to each other, compared to cases where the location of the data pair has changed relative to each other. And the accuracy of the comparison obtained from the proposed method, in this case, increases compared to other data pair placement modes.
Geographic Data
Amir mohammad Salehabadi; Seyed Hadi Ghoddusifar; Ali Mohammadpour
Abstract
Extended AbstractIntroductionOne of the most important consequences of the rapid growth of urbanization and the physical development of Iranian cities in recent decades has been the disintegration of the distribution system of urban service centers. Urban parks and green spaces played a special role ...
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Extended AbstractIntroductionOne of the most important consequences of the rapid growth of urbanization and the physical development of Iranian cities in recent decades has been the disintegration of the distribution system of urban service centers. Urban parks and green spaces played a special role in creating this social inequality for citizens' access to city services. Park green spaces (PGS) are considered essential public infrastructure due to the benefits they have for urban residents. Such benefits include recreation, viewing natural landscapes, protecting the urban environment, preventing disasters, and improving the quality of life. According to the worrying consequences of the urban landscape planners regarding the imbalance in the spatial distribution of urban green spaces, it seems that the ideas and theories attributed to urban greening and universal access to desirability Green cities have the potential to act as a decisive force in the main agenda. Similar to the ideal of "public goods" and the diffuse benefits of access, green goals can serve as a means to de-emphasize asymmetric power relations and conflicts over competing resources, which risk re-creating unjust outcomes. In this article, the ASD index (Equation1) of Lee and Hong (2013) is used to measure the level of shortage or excess supply of urban park services. One of the innovative aspects of this research is the use of the distributive justice index to measure ASD, which is introduced as new ASD. With the help of this index, it is possible to find out how effective each park is based on the index received through the calculations made in the supply and demand model. In other words, this article measures the quality of locating parks in the supply and demand model with the effect of their spatial distribution justice. This causes that in addition to the longitudinal distance between parks and residential blocks, the factors affecting their public services will also be involved in the calculations to bring the findings closer to the current situation. Many studies have been conducted on the topic under discussion. Materials & MethodsThis study is an information modeling research. For that purpose, it's practical and developmental research to measure the degree of the supply shortage or demand excess for urban park facilities. In other words, the present study uses situational weight index and distributive justice for ASD. This research is mixed regarding data collection methods, relies on library methods to review resources, selects 50 points for field observations to collect location information, and extracts the required parameters to create a database based on reference land information. This research will be dependent on the modeling analysis method and using GIS analysis functions. The analysis of input data, including qualitative and quantitative information, is performed using standard coding and weighting methods. ASDi, which is the quantitative difference between supply and demand in park services per unit area ('area' hereafter), is defined as follows .This research was used by combining the positional weight index and distribution justice for ASD to explain the new ASD index(Equation2).Equation. #1 Equation2: Results and discussion To measure the spatial justice of an urban park, mathematical communications and formulas will be used in this study, which the authors optimize to suit the specific conditions of the parks. Indicators are:› Determining the share of each park in the population under the sphere of influence,› Measuring the efficiency of parks,› The distance of residential blocks from parks,› The population of residential blocks in the sphere of influence of parks. ConclusionThe findings of this study show that parks that have high park efficiency, the final branches of spatial justice of parks are also high, with the difference in areas where ِMetropolitan and Regional parks are adjacent to neighborhood parks. The final index of spatial justice improves and expands the parks relative to their efficiency.Based on the empirical analysis, the spatial disparities can be even greater when service availability and population demand are high. City planners should decide to build new parks by considering areas where demand is higher than the supply, not just based on whether there are many parks nearby because residents in the densely populated areas may suffer from a lack of services even though many parks are located nearby.The “new ASD” method has advantages for studying the parks of Region 1 of Tehran, which can be summarized as follows:New ASD can be interpreted intuitively because the results are measured in square meters, which should provide more parking spaces or the number of people at risk of park shortages. The per capita green space parameter allows the demand unit to be equated with supply, allowing planners to easily calculate the size of parks that should be more in priority and low supply areas.The results of the analysis can be obtained based on determining the geographical coverage of the park services. Based on the planning information drawn using legal criteria, planners can support their arguments about the location of other parks by recognizing spatial inequality.Although different social groups were not considered in the analysis, like other studies that looked at ethnic subclasses to highlight park service inequality among different ethnic groups, the methodological process of new ASD estimation can be easily extended to apply to different social groups. For example, some landscape planners In Tehran, they may be interested in studying spatial inequality, for example, people with disabilities, different age groups, or men and women separately.
Gholam Hossein Eskani Kazazi
Volume 21, Issue 84 , February 2013, , Pages 85-94
Abstract
Gorges are considered ont of the most attractive and complicated phenomena in geomorphology. Their Complexities have led to some hypotheses about their formation. Some of these hypotheses are considered classics of the field now. In this research, many methods have been employed in studying of the transverse ...
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Gorges are considered ont of the most attractive and complicated phenomena in geomorphology. Their Complexities have led to some hypotheses about their formation. Some of these hypotheses are considered classics of the field now. In this research, many methods have been employed in studying of the transverse valley of Tang-Takab, such as topographic and geologic maps and aerial-photos.The valley is located in anticline of khaviz in northeast of Behbahan. In surveying the area, several observations were made. We tried to clarify how these gorges were formed in the late cretaceous (Goorpi construction) Ecocene (pabdeh construction) Oligo – Miocene (Asmany calcareous construction) accompanied with Quaternary alluviums. Based on new hypotheses, the progress of formation of gorges in the transverse valley of Tang Takab became clear. The processes are active in changing a vast area in zagrus mountain. Therefore, for interpretation of this phenomenon there is no need to draw on mechanisms, accidents or hypotheses. It should be noticed that formation of transverse valley of Tang-Takab is not related to only one specific process, but to several factors which have happened simultaneously
Extraction, processing, production and display of geographic data
Masoud Eshghizadeh
Abstract
Extended Abstract Introduction The best and most effective way to control wind erosion is to increase vegetation to cover the land surface. The roughness of the land surface is increased by vegetation. Because it increases the friction that causes a decrease in wind speed on the surface of the ground ...
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Extended Abstract Introduction The best and most effective way to control wind erosion is to increase vegetation to cover the land surface. The roughness of the land surface is increased by vegetation. Because it increases the friction that causes a decrease in wind speed on the surface of the ground and the carrying capacity of sediments by the wind. By determining resistant species and more adapted to dry conditions, it will be possible to establish vegetation in these areas in different non-desertification projects to control and reduce wind erosion.Materials & Methods In this research, in one of the critical centers of wind erosion in Gonabad County in northeastern Iran, investigated the performance of a biological project of non-desertification operations with Haloxylon aphyllum, Haloxylon persicum, Seidlitzia rosmarinus, Nitraria schoberi, Atriplex canescens and annual plants in different intensities of the drought for 2004 to 2021. At first, using the RDI index, drought intensities were determined in March, April, and May in the studied period. In the next step, the maximum, average, and minimum values of NDVI, TDVI, SAVI, and EVI indices were calculated using Landsat satellite images and data processing ENVI 5.3 software in each of the covered areas by desired specie in the studied months. In the final stage, the values of these vegetation indices were compared and analyzed for drought intensities in the areas and months.Results Based on the results, in all the indices, the area covered by Seidlitzia rosmarinus had a better condition than in other areas in the very dry drought intensity and with the highest value of 0.341 in the EVI index. But in the medium and mild drought intensities, the area covered with the Haloxylon sp had a better condition than in other areas and with the highest value of 0.456 in the TDVI index. However, all studied vegetation indicators did not show any significant difference between the planted areas. In March with the very dry condition, vegetation was more dependent on the intensity of dry conditions in February. The severity of the drought in February caused the values of all vegetation indicators in March in the studied areas to be negative, except in the annual species area. In March, the SAVI index, in April TDVI index, and in May TDVI and EVI indices had better ability to distinguish vegetation cover. The results of the Kruskal-Wallis test showed that in March, there was a significant difference between high, medium, and mild dry conditions only for the TDVI index at the level of 5% and the SAVI index at the level of 1%. In April, the NDVI and SAVI indices at the level of 1% and the EVI index at the level of 5% showed a significant difference between the three dry conditions. The results of the Mann-Whitney test showed that in May, only the SAVI index had a significant difference at the level of 1% between the moderate and mild dry conditions.Discussion & Conclusion The results confirmed the ability of vegetation indices obtained from Landsat satellite imagery to monitor the vegetation changes due to the drought. All the indices showed changes in the vegetation in the drought conditions, but no difference was seen between the vegetation areas. The resistance of the species to drought was one of the main reasons that caused there to be no significant difference between the vegetation areas, but the difference between the drought conditions was significant. Due to the adaptation and resistance of desert species to drought conditions, their sensitivity to drought in dry and desert areas is lower than in humid areas. In the condition that February is affected by drought, the cover conditions of annual plant species in the studied area in March were better than in other areas. But in March with very dry or moderate drought conditions, the cover conditions of Seidlitzia rosmarinus species were better coverage than in other areas. Based on the results, in the continuation and occurrence of moderate to high drought in April and May, the area of Seidlitzia rosmarinus showed a better cover than in other areas. In the condition of continued drought in March, annual plants do not have a chance to grow and the species that can use the moisture reserve in the deeper soil will have more opportunity to cover the surface of the ground, which this research showed that among the species in this area, Seidlitzia rosmarinus has more ability. Therefore, the principle of mixed planting and preventing single planting in the desert restoration and non-desertification projects should be emphasized and implemented.
Extraction, processing, production and display of geographic data
Hossein Asakereh; Fatemeh Motevali Meydanshah; Leila Ahadi
Abstract
Extended Abstract
Introduction
Temperature is a significant atmospheric element that manifests climate change, specifically global warming resulting from an increase in greenhouse gas concentration. Atmospheric simulation is a critical tool in studying changes in atmospheric-climatic elements, particularly ...
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Extended Abstract
Introduction
Temperature is a significant atmospheric element that manifests climate change, specifically global warming resulting from an increase in greenhouse gas concentration. Atmospheric simulation is a critical tool in studying changes in atmospheric-climatic elements, particularly temperature.
The most commonly used tool for simulating the responses of the climate to greenhouse gas increases and examining future temperature changes is the use of climate variables simulated by coupled atmosphere-ocean models (AOGCMs). General circulation models (GCMs) are powerful tools aimed at generating climate scenarios. However, GCMs cannot provide effective information on climate simulation at local and regional scales. Therefore, the downscaling method is used to bridge the gap between local and global scales.
The current research aims to simulate maximum temperature using an artificial neural network model that adopts data from the atmospheric general circulation model (HadCM3) under RCP8.5, RCP4.5, and RCP2.6 scenarios for the Yazd synoptic station from 2006 to 2095. The independent variable, as the input to the artificial neural network, was selected for statistical downscaling using four statistical criteria: Percentile Reduction, Backward Variable Elimination, Forward Variable Selection, and Stepwise Variable Entry. Finally, the maximum temperature of the Yazd synoptic station for the next century was simulated.
Data and Methodology
The present study aims to investigate the maximum temperature of Yazd's synoptic station in the context of climate change based on valid scenarios until 2095. To achieve this, three sets of data were used: average daily maximum temperature data from Yazd's synoptic station, observed atmospheric data for the period of 1961 to 2005 (NCEP data), and simulated data from 2006 to 2095 based on release RCP scenarios. The NCEP data from 1961 to 2005 included 26 atmospheric variables that will be used as independent or predictor variables.
Modeling, simulating, and forecasting temperature based on nonlinear and chaotic time series is a challenging task. Prior studies have shown that artificial neural networks (ANNs) are suitable for simulating and predicting basic processes that are not well known. It is crucial to select the correct input variables intelligently and according to the purpose of the artificial neural network's design for prediction and simulation. Accordingly, in this study, the most suitable atmospheric parameters as the input of the artificial neural network were selected by pre-processing and selecting the atmospheric variables for the base period (1961-2005) to simulate with four statistical criteria (Percentile Reduction, Backward Variable Elimination, Forward Variable Selection, and Stepwise Variable Entry). The resulting mean square error (MSE) obtained from the statistical criteria was compared, and the correlation coefficient and the similarity of the monthly time series trend of the simulated values with the target values were also analyzed. The best network architecture was selected to simulate the maximum temperature of Yazd's synoptic station from 2006 to 2095 under different RCP emission scenarios.
Discussion
The selection of explanatory variables for downscaling was based on four statistical methods: Percentile Reduction, Backward Variable Elimination, Forward Variable Selection, and Stepwise Variable Entry. After analyzing the mean square error (MSE), correlation coefficient, monthly average values of the maximum temperature of Yazd station, and estimated values from 1961 to 2005, the probability density function, cumulative probability function, and monthly time series trend obtained from all four methods, the explanatory variables were selected. These variables include mean sea level pressure, the divergence of 1000 hPa, zonal wind component, zonal wind intensity of 850 and 500 hPa, altitude and vorticity of 500 hPa, average temperature, and relative humidity at a 2 m height.
The structure and architecture of the neural network were designed based on these selected variables. The network consisted of a two-layer feedforward, with a sigmoid transfer function in the hidden layer, a linear function in the output layer, an input layer with eight variables, eight neurons, and the Lunberg-Marquardt training algorithm. This architecture was used to simulate the maximum temperature of Yazd's synoptic station under RCP2.6, RCP4.5, and RCP8.5 scenarios for two periods of 2050-2006 and 2095-2051.
Comparing the monthly average values of RCPs (RCP2.6, RCP4.5, and RCP8.5) in the first statistical period (2050-2006) with the base period (1961-2005), the maximum temperature of Yazd station indicates an increase in temperature in winter, spring, and summer, and a decrease in the autumn season under all three RCPs.
Comparing the monthly mean values of RCPs (RCP2.6, RCP4.5, and RCP8.5) of the second period (2051-1995) with measured mean maximum temperature (2005-1961) showed that temperature will increase the most in winter, spring, and summer, similar to the first period of the RCP8.5 scenario. In this scenario, unlike the other scenarios, the increase in temperature is evident in both subperiods for the autumn season. Finally, in the second period (2051-1995), the increase in the average maximum temperature of Yazd station in winter, spring, and summer, and the decrease in the average maximum temperature in autumn will be more significant.
Conclusion
The increase in greenhouse gas concentration resulting from human industrial activities is expected to cause global and regional warming in the future. The current study's findings indicate that the average maximum temperature of Yazd station will rise between 0.4 to 6.9 in winter, 0.2 to 8.1 in spring, and 1.1 to 7.7 in summer from 2006 to 2095. However, a decrease in the maximum temperature between 0.6 and 1.4 is expected in autumn. These results are consistent with those of other researchers.
Iran Ghazi
Volume 1, Issue 4 , May 1992, , Pages 14-21
Abstract
About two hundred million years ago, Africa and Arabia were a single continental block. However, at the beginning of the Mesozoic, they started to separate. This process reached its peak during the Tertiary, and still continues. The resulting depression between Africa and Arabia, which was continuously ...
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About two hundred million years ago, Africa and Arabia were a single continental block. However, at the beginning of the Mesozoic, they started to separate. This process reached its peak during the Tertiary, and still continues. The resulting depression between Africa and Arabia, which was continuously widening, was filled with water, thus forming the Red Sea, the Gulf of Aden and the Bab-el-Mandeb Strait between the Red Sea and the Gulf of Aden.
The break of the Earth's Crust and separation of the two continental blocks of Asia and Africa from each other in this region and appearance of the Red Sea and the Gulf of Aden have brought about one of the most distinctive geological structures, namely that of great graben of Africa and Asia. A branch of this graben advances into east of Africa; it starts from Ethiopia and continues in the Africa’s break toward south through Kenya and Tanzania as far as Zimbabwe. In the north of the Red Sea, the appearance of the Suez and Aqaba Gulfs and the continuation of the Aqaba gap in the Jordan Valley to the Dead Sea are also part of the tectonic process of the whole region of Southwest Asia and the East and North East of the African continent.
The above-mentioned processes, which are very typical examples of the Wegener Continental motion theory, are displayed much better in satellite imagery than topographic maps. In this paper, using satellite imagery and with the help of scientific texts and different maps and atlases, the region’s map, especially where the images had no no cloud cover, has been prepared and due interpretation has been made.
Mohsen Saghaei
Volume 11, Issue 44 , February 2002, , Pages 17-18
Abstract
Human communication is the cornerstone of human society without which the culture, as the characteristic of human society, never appears.On the other hand, the development of electronic communications has made the modern society so distinct from societies of the past that some call the modern times are ...
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Human communication is the cornerstone of human society without which the culture, as the characteristic of human society, never appears.On the other hand, the development of electronic communications has made the modern society so distinct from societies of the past that some call the modern times are the era of communication. Today we live in the age of communication, which has its own characteristics. The best feature of the age of information is facilitation and acceleration of communication. In this paper, we have tried to discuss information and communication and their impact on future cities, and to analyze the impact of information and communication on the creation of a global village.
Ghodratallah Abedi
Volume 8, Issue 32 , February 1999, , Pages 20-30
Abstract
Earthquake, as the most horrifying and tragic natural disaster, knows no limitations. Since Iran is located on one of the most active seismic belts in the world (the Alps-Himalaya orogenic belt), it is considered as one of the most earthquake - prone countries in the world. Kerman Province, due to its ...
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Earthquake, as the most horrifying and tragic natural disaster, knows no limitations. Since Iran is located on one of the most active seismic belts in the world (the Alps-Himalaya orogenic belt), it is considered as one of the most earthquake - prone countries in the world. Kerman Province, due to its position on this belt, is seriously vulnerable to dangers by this natural disaster. Earthquakes occurred in this province have always entailed vast human losses and economic damages. In this paper, it has been tried to study the recorded data and the geomorphological map of the area, and to determine sensitive and vulnerable points over the province and provide the economic and social planners and managers and officials of emergency aid organizations with suggestions for reduction of the effects of natural disasters.
Hosein Asakareh
Volume 11, Issue 41 , May 2002, , Pages 21-23
Abstract
Modeling means presenting a complex situation in a simple and hypothetical manner, with emphasis on some aspects and attributes and removing others in order to recreate the status of the past and predict the future. The first modellings were performed on the atmosphere. Then, by using other branches ...
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Modeling means presenting a complex situation in a simple and hypothetical manner, with emphasis on some aspects and attributes and removing others in order to recreate the status of the past and predict the future. The first modellings were performed on the atmosphere. Then, by using other branches of scientific knowledge, climate modeling was carried out.Climate models fall into four categories of Energy Balance Models (EBM), Radiation-Convection Models (RCMs), Statistic-Dynamic Model (SDM) and general Circulation Models (CCM).
General Circulation Models of the atmosphere determine the three-dimensional climate indices in networks and calculate dynamic and thermodynamic processes in each network and from one network to the other based on basic equations of movement and in different time and spatial periods and atmospheric levels.Finally, the content and foundation of these models are based on dynamics, physics and levels affecting the dynamics and physics of the climate.
Borumand Salahi
Volume 14, Issue 55 , November 2005, , Pages 22-25
Abstract
The difference in air pressure of two different points on the surface of the Earth causes the flow of air from the high-pressure zone to the low-pressure one. In meteorology this flow is called "wind". Wind is one of the meteorological parameters that is widely considered in developmental and spatial ...
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The difference in air pressure of two different points on the surface of the Earth causes the flow of air from the high-pressure zone to the low-pressure one. In meteorology this flow is called "wind". Wind is one of the meteorological parameters that is widely considered in developmental and spatial planning. In municipal engineering and urban planning, attention to dominant wind direction is a necessity in the construction of structures. In agricultural meteorology, particular attention is paid to the wind factor. The wind study is important in air transportation and location of airport construction. Considering the increasing consumption of fossil fuels such as oil, gas, coal, etc., and their non-renewable reality, advanced and developing countries are paying special attention to new energies, especially wind power. Therefore, attention to the direction and speed of wind is one of the necessities in regional studies. The wind direction and speed are analyzed after drawing the wind rose. Therefore, in this article, a software for drawing wind rose is briefly described.
Iraj Maghfuri Moghaddam; Mahmoud Jalali
Volume 13, Issue 51 , November 2004, , Pages 23-26
Abstract
Like other natural phenomena of the universe, the inclination angle of the axis of the Earth is significantly variable. These changes can be divided into two groups. First, regular cyclic changes of the inclination angle of the Earth, which is part of the Milankovitch changes, and whose magnitude of ...
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Like other natural phenomena of the universe, the inclination angle of the axis of the Earth is significantly variable. These changes can be divided into two groups. First, regular cyclic changes of the inclination angle of the Earth, which is part of the Milankovitch changes, and whose magnitude of positive and negative values in every 41,000 years are plus and minus 3.5. The second, long-term geological changes of the Earth's inclination angle, which seems to be one-sided and gradually decreasing since the beginning of the Phanerozoic Era (450 million years ago). Factors such as friction caused by tidal waves and separation of the Earth’s Flesh and Crust have contributed to this phenomenon. Long-term changes in the inclination angle of the Earth and its decrease have caused the formation of seasons as well as climatic division of geographic latitudes.
Roghiyyeh Golvari (Translator)
Volume 11, Issue 42 , August 2002, , Pages 24-26
Abstract
In this paper, the GLONASS system and its certain aspects that affect the positioning of the carrier phase are examined and the current state of the GLONASS system has been considered. The results show that positioning can be achieved using the GLONASS carrier phase, and the combined use of both GLONASS ...
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In this paper, the GLONASS system and its certain aspects that affect the positioning of the carrier phase are examined and the current state of the GLONASS system has been considered. The results show that positioning can be achieved using the GLONASS carrier phase, and the combined use of both GLONASS and GPS systems has valuable advantages in comparison with the use of the GPS system alone.
Hamid Malmirian (Translator)
Volume 10, Issue 40 , February 2001, , Pages 24-31
Abstract
Forestry management considers forests for wood, forage, water, wildlife and recreation.Since the main and raw product of forest is wood, forestry especially considers management of lands that contain logging trees, restoration and improvement of forest condition and fire control. Approximately a third ...
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Forestry management considers forests for wood, forage, water, wildlife and recreation.Since the main and raw product of forest is wood, forestry especially considers management of lands that contain logging trees, restoration and improvement of forest condition and fire control. Approximately a third of the earth is covered by various forest types. They have been irregularly distributed and their capital values change regularly. Interpretation of aerial photographs provides an easy way to check their condition.
Mahdi Modiri
Volume 8, Issue 31 , November 2009, , Pages 24-30
Abstract
The color of maps has a special importance in cartography. Legibility and clarity of a map and its agreement with reality (nature) is fulfilled with the help of colors. Application of various colors in map is carried out according to natural conditions and land features and the aim and scale of maps ...
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The color of maps has a special importance in cartography. Legibility and clarity of a map and its agreement with reality (nature) is fulfilled with the help of colors. Application of various colors in map is carried out according to natural conditions and land features and the aim and scale of maps based on principles of cartography. Selection of colors in maps should be from esthetic point of view and accompanied by artistic qualities that can help introduce the face of the earth better and add to the map’s delicacy.In the issue of maps’ color some basic considerations such as choice of color and the method of implementation of colored print should be taken into account so that color design of maps can increase the practical values of maps.
Mohammad Ghasem Torkashvand
Volume 4, Issue 15 , November 1995, , Pages 24-31
Abstract
In general, vegetation of Lorestan is varied and including many different species. The composition and characteristics of these forests vary by change in latitude, altitude, precipitation, compression and direction of ground features, and lengths of cold and hot seasons. Vegetation in Lorestan is divided ...
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In general, vegetation of Lorestan is varied and including many different species. The composition and characteristics of these forests vary by change in latitude, altitude, precipitation, compression and direction of ground features, and lengths of cold and hot seasons. Vegetation in Lorestan is divided into two categories: forests and (small) plants, which we will discuss in detail. In terms of geographic dispersion, since most of the Lorestan forests belong to the Khorramabad area in the south of Lorestan, explanation about Lorestan forests is the same as explanation about forests of the Khorramabad city (except for the eastern parts of Oligudarz district).
Fatemeh Razi'ee
Volume 4, Issue 13 , May 1995, , Pages 24-34
Abstract
In this study, in order to determine effective geographical factors in terms of potential and natural talent and development, and to recognize the constraints and complications caused by the developmental trend under the heading of the evolution and directions of the expansion of Tehran, a model has ...
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In this study, in order to determine effective geographical factors in terms of potential and natural talent and development, and to recognize the constraints and complications caused by the developmental trend under the heading of the evolution and directions of the expansion of Tehran, a model has been proposed in urban and rural studies. This study has employed the knowledge and technology of graphic information (map, aerial photos, satellite imagery), and through exploiting maps, pictures and images produced at different times from Tehran, has collected broad information about the development and evolution and development directions and, while carrying out examples of land surveying and fieldwork, has verified the information in order to provide planning for city construction and improvement.
Zoleikha Bagheri (Translator)
Volume 10, Issue 39 , November 2001, , Pages 25-34
Abstract
The role of astronomers in life: the picture on this page showing human beings at exploration was painted in 1947 by Rufino Tamayo. In this work, the effort of modern human for recognition of the universe is described. Certain moons and comets can be witnessed in the sky. Geometric shapes in the background ...
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The role of astronomers in life: the picture on this page showing human beings at exploration was painted in 1947 by Rufino Tamayo. In this work, the effort of modern human for recognition of the universe is described. Certain moons and comets can be witnessed in the sky. Geometric shapes in the background represent celestial and planetary images. The red radio tower which sends out signals indicates the existence of civilization on other planets…
Zoleikha Bagheri (Translator)
Volume 10, Issue 38 , August 2001, , Pages 25-39
Abstract
• Each of the storms of Jupiter last for more than three centuries.• What does the clear color of Jupiter indicate?• There is probably no solid surface under Jupiter’s clouds.• The planet is capable of releasing radio waves with a power of 400 billion watts.• A massive ...
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• Each of the storms of Jupiter last for more than three centuries.• What does the clear color of Jupiter indicate?• There is probably no solid surface under Jupiter’s clouds.• The planet is capable of releasing radio waves with a power of 400 billion watts.• A massive five-million Ampere current is on between the Io satellite and Jupiter.• The volcanic mountains on the surface of Io revolve the satellites outward.
Peter Grego
Volume 3, Issue 12 , February 1994, , Pages 25-27
Abstract
Full lunar eclipse is one of the most interesting scenes in astronomy. Until now, not two of the observed lunar eclipses have been completely similar. All solid heavenly bodies, which receive light from the sun, create a shadow in space. The extent of this shadow depends on the size of the mass and its ...
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Full lunar eclipse is one of the most interesting scenes in astronomy. Until now, not two of the observed lunar eclipses have been completely similar. All solid heavenly bodies, which receive light from the sun, create a shadow in space. The extent of this shadow depends on the size of the mass and its distance from the sun. There are two main elements in these shadows, which are Umbra and Penumbra.
Ahmad Taghdisi; Seddigheh Kiani; Farnaz Abolhasani; Zahra Soltani
Volume 20, Issue 78 , August 2011, , Pages 26-32
Abstract
Given the resource limitations and the upward trend of development, if this movement is not accompanied by proper management and planning, it can create problems. Because any development requires the exploitation and use of natural resources. Therefore, it can have direct or indirect effects on nature. ...
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Given the resource limitations and the upward trend of development, if this movement is not accompanied by proper management and planning, it can create problems. Because any development requires the exploitation and use of natural resources. Therefore, it can have direct or indirect effects on nature. Optimal use of soil and water resources and ways to predict and reduce their problems have always been the objectives of correct and principled agricultural development in order to obtain the highest returns from the minimum resources. Water use optimum management has been the subject of much discussion in many expert circles in the past few decades, in all of which, emphasis has been placed on monitoring and evaluation as the keys to success. Many irrigation and drainage networks operate on the basis of supply and demand management and usually deliver water regardless of the actual water requirement. In irrigation and drainage networks, due to the scattering of farms, the size of the land, the variety of cultivation and the distance between the place of extraction and the point of delivery, management of utility and maintenance is not possible without taking the interactions of the above factors into account. Moreover, in irrigation networks, descriptive data is produced daily on a massive scale that requires organizing, analyzing and deciding, which are very difficult with traditional methods and requires the use of the new systems such as GIS and remote sensing. The purpose of this paper is to investigate the geographic information system and remote sensing and their application in irrigation and drainage networks management.
Hamid Malmirian (Translator)
Volume 13, Issue 49 , May 2004, , Pages 26-30
Abstract
Today, most of the water found on the surface of the earth is in lakes and oceans in the form of liquid. Almost two percent of water is in the form of solid as ice at high altitudes and geographic latitudes. About ten percent of the earth’s surface is covered by glaciers. Over a million years or ...
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Today, most of the water found on the surface of the earth is in lakes and oceans in the form of liquid. Almost two percent of water is in the form of solid as ice at high altitudes and geographic latitudes. About ten percent of the earth’s surface is covered by glaciers. Over a million years or more, the glaciers have consistently been on over 30% of the earth's surface. The main era took place during periods when the earth’s climate was colder than its current state. The formation of glaciers occurred both in the form of formation of a "glacier in the valley” in which ice occupied the mountainous valleys, and in the form of continental glaciers in which large parts of several continents were covered with ice with a thickness of three kilometers. This arouses humans into thought and helps them describe the advancing ability of a glacier to cut land features along its course. We rationally discuss the formation of sedimentary lands due to formation of continental glaciers. Four distinct stages have been identified in the United States. The last ice age has been during the formation of the Wisconsin Glaciation, which occurred within a time interval between 70,000 and almost 10,000 years ago.
Alireza Owsati
Volume 9, Issue 35 , November 2000, , Pages 26-33
Abstract
The Moon is undoubtedly the nearest celestial body to Earth, and in other words it is the only neighbor that is ready to accept the uninvited guests from our Planet. It is also considered as the Earth’s only satellite. The Moon has since ancient times attracted the attention of the Earth’s ...
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The Moon is undoubtedly the nearest celestial body to Earth, and in other words it is the only neighbor that is ready to accept the uninvited guests from our Planet. It is also considered as the Earth’s only satellite. The Moon has since ancient times attracted the attention of the Earth’s habitants, and it has been the subject of many explorations and research regarding its formation and characteristics, and even many poetic minds have fancied about it and likened it to the eyebrows or face of the beloved. Curious human being managed to step on it about thirty-one years ago. This conquest put an end to all false claims and speculations about the Moon. When the veil was done away with and the facts were revealed, it become clear that the Moon, despite its beauty, is but a dead planet, because no sign of life was found on it. There was indeed nothing but an eternal deadly silence, earlier knowledge of which could have saved people those great amounts of praise and speculations.
Abbas Khosravi (Translator)
Volume 8, Issue 29 , May 1999, , Pages 26-29
Abstract
Preparing of land use maps is of great importance in terms of assessment of current situation, land utilization and examination of problems preventing more satisfactory land use.
One of the techniques whose resultant information can be used as the source for preparation of land use maps is ground resource ...
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Preparing of land use maps is of great importance in terms of assessment of current situation, land utilization and examination of problems preventing more satisfactory land use.
One of the techniques whose resultant information can be used as the source for preparation of land use maps is ground resource satellites which receive information from the ground level, and present it after certain stages and through different ways.
This translated paper shows that the information from the IRS-1C satellite can be useful in development of proper methods for preparation of land use maps due to its special characteristics.
Gholamreza Delafkaraan
Volume 1, Issue 1 , May 1990, , Pages 26-31
Abstract
Up to ten years ago, when talking about selecting an airplane for shooting, we were looking for features such as: good standing power, large wing, vast operating range and, most importantly, low or medium speed. The low speed of the shooting aircraft was favorable in the sense that, when the camera’s ...
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Up to ten years ago, when talking about selecting an airplane for shooting, we were looking for features such as: good standing power, large wing, vast operating range and, most importantly, low or medium speed. The low speed of the shooting aircraft was favorable in the sense that, when the camera’s light valve was opened, the stretch of the features across the surface of the image, caused by the forward movement of the aircraft, be kept as small as possible, not exceeding 25 microns. This would prevent the selection and use of films whose sensitive layers had greater power of recording or resolution, because the speed of recording of these films is very low due to small-grained crystals in their emulsion, and must therefore be exposed to light for longer periods of time. In order to avoid the elongation of the image, a low-speed aircraft and fast films (with large-grained crystal and low resolution) were used to provide a good image in a very short time through receiving proper amount of light.
Reza Mo'menzadeh
Volume 16, Issue 64 , February 2008, , Pages 27-34
Abstract
A country that suffers from a lack or non-existence of national power sources will surely fail to fulfil its national security. Geography is still considered as one of the main factors, and in a sense, the most stable element of national power. The relationship between geography and strategy can be considered ...
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A country that suffers from a lack or non-existence of national power sources will surely fail to fulfil its national security. Geography is still considered as one of the main factors, and in a sense, the most stable element of national power. The relationship between geography and strategy can be considered from two points of view. First, it can be studied through examining opportunities and limitations that geography as an important source of national power offers in relation to the country’s strategy of national security. Second, consideration of the fact that ensuring the security of geographic space in which humans live and with which have ecological connection is very important. Consequently, sometimes geography affects national security and sometimes security affects land and geography. Therefore, determining its role and position in the process of developing a national security strategy requires correct recognition of the basic concepts related to geography and national security.
Maryam Bayati Khatibi
Volume 15, Issue 59 , November 2006, , Pages 27-32
Abstract
Understanding natural issues and the way natural phenomena operate, whether in order to enjoy their benefits or to deal with their adverse effects, must be accompanied by observation and interpretation of phenomena. Proper interpretation and accurate analysis of the results of observations requires necessary ...
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Understanding natural issues and the way natural phenomena operate, whether in order to enjoy their benefits or to deal with their adverse effects, must be accompanied by observation and interpretation of phenomena. Proper interpretation and accurate analysis of the results of observations requires necessary and sufficient information concerning the events’ ways of occurring and the past history of phenomena. In natural problems such as landslides, earthquakes, etc., and in historical issues and requirements of humans such as nutrition, habitation, water pollution, etc., the instantaneous recognition or the course of changes in time as well as historical comparison of magnitude of changes are duly considered, and geographers can well examine this issue and consider, in their studies on large expanses of land, how short-term changes occur during the phenomenon, and, by referring to these changes, generalize the results to the future and predict the intensity and extent of future events. Thus it can be said that natural geography perceives the momentary balance of phenomena, or at least seeks to understand it, and even takes time backward or forward on a scale of human history. In other words, the present form of the Earth and the current conditions in any given phenomenon are of great concern to geographers, but accurate information from the past is always needed for their accurate examination. Furthermore, there is a need for predictions about the future trend based on current trends and past information when considering long-term exploitation of natural resources. According to the above-mentioned matters, it can be clearly stated that the study of changes in phenomena over time is the basis of geography studies, especially natural geography. Fortunately, today with the development of communications, it is possible to extend the scope of these studies to different spaces with various features, and also to collect more information; on the other hand, using new methods, techniques and facilities, the horizons of vision in the past, and in some cases in the future, have become more extensive.
Shahriar Khaledi
Volume 6, Issue 22 , August 1997, , Pages 27-33
Abstract
Today circulation of water on earth, amounting to about 500,000 billion cubic meter, is well recognized by experts in the field despite its all complexities. Experts show great interest in examination of water circulation and determination of quantities of different water flows (precipitation, rivers, ...
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Today circulation of water on earth, amounting to about 500,000 billion cubic meter, is well recognized by experts in the field despite its all complexities. Experts show great interest in examination of water circulation and determination of quantities of different water flows (precipitation, rivers, lakes, aquifers, etc.) which form the totality of the earth’s water. Currently the issues concerning natural water resources are also studied. Generally, distribution of fresh waters around the world is very irregular, so that they might be completely inaccessible exactly where there is need for great amounts of such waters. For some fundamental reasons, if water resources are renewable, they are considered as among flows and in certain cases follow global scales. But in some countries, there are significant resources of unrenewable water, just as hydrocarbon and mineral resources. Numerical assessments of volume of water resources have been carried out on different scales and according to different parts of hydrosphere, and have revealed significant exploitation of such resources; these studies included oceans, polar ices, underground waters, soil moisture, lakes, rivers and atmosphere. M.L. l’Vovich has calculated the average periods of renewal of the above resources as follows: Oceans: three thousand years; aquifers: four to five thousand years; ice coverage, polar ice and continental glaciers: eight thousand years; lakes: seventeen thousand years; soil moisture: one year; rivers: almost twelve days; atmospheric humidity: one week. In absolute conditions, underground water is almost in correspondence with natural circulation of water. However, mineral resources take very long periods of time for renewal. Therefore, they can be considered as unrenewable on human life-span scales.
Abbas Khosravi
Volume 5, Issue 17 , May 1996, , Pages 27-41
Abstract
The study area is located in central Iran and in the southern margin of a large depression along the northwest-southeast direction. This region is a desert part of which is formed by salt pan (Kavir). This region, like most of Iran's central areas, has been swept by sand for many years. The issue of ...
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The study area is located in central Iran and in the southern margin of a large depression along the northwest-southeast direction. This region is a desert part of which is formed by salt pan (Kavir). This region, like most of Iran's central areas, has been swept by sand for many years. The issue of sand is most threatening toward villages in the north and northeast of Kashan, namely Aran and Bidgol, and four villages of Abu Zaidabad, including Mohammad Abad, Gaz, Fakhra, Qasim Abad, Yazd Delan and Hossein Abad. It covers houses, roads, water wells and fields, and increases aridity in the area. Kashan region is a small part of a natural, morphologic and geologic unit, divided into two distinct parts:
A) Raised areas known as the southern part of Kashan mountain range, or Karkass mountain range,
(B) Depression of Qom-Kashan-Ardakan Qom-Kashan-Ardakan depression is in fact a wide plain valley that is limited to volcanic rocky mountains, and the faults lying all along the foot of this mountain range have caused it to rise. This depression, due to thick and folded deposits of Neogene red layers which are partly degraded, is filled in the sea section of Qom formations which is of the Oligo-Miocene age, and is covered by Bahada deposits, sand, large rubbles, playa sediments and finally sandy hills.
Taghi Tavoosi; Mohsen Armesh
Volume 21, SEPEHR , February 2013, , Pages 28-30
Abstract
From a meteorological point of view, frost occurs when minimum daily temperature decreases to 0 °C. This study seeks to predict and rout early autumn frosts in Khash city. To study early frosts, the first day of frost in the statistical period of 1986 to 2008 was investigated. Probabilities and return ...
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From a meteorological point of view, frost occurs when minimum daily temperature decreases to 0 °C. This study seeks to predict and rout early autumn frosts in Khash city. To study early frosts, the first day of frost in the statistical period of 1986 to 2008 was investigated. Probabilities and return periods of autumn frosts (early frosts) were estimated using normal distribution and Log Pearson type 3 distribution. In Log Pearson type 3 distribution, there is 99 percent probability that frost does not begin before 8 October, 95 percent probability that frost does not begin before 15 October. In normal distribution, there is 95 percent probability that frost does not begin before 12 October. Coefficient of data change is 21.2 which indicates relatively high frequency in the time of frost. A graph of the first day of frost and its 11 year average was prepared and frost occurring process was routed. Results indicate that during the last decades frost has retreated toward winter.
Davood Majidi
Volume 20, Issue 77 , May 2011, , Pages 28-35
Abstract
Today, microwave remote sensing is very important in the investigation and monitoring of the surface of the earth and its features. The microwave remote sensing is basically dependent on the accurate recognition of the interactions of these waves with different levels of the earth, such as soil, water, ...
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Today, microwave remote sensing is very important in the investigation and monitoring of the surface of the earth and its features. The microwave remote sensing is basically dependent on the accurate recognition of the interactions of these waves with different levels of the earth, such as soil, water, vegetation, etc. Without such recognition, it is not feasible to adopt efficient and effective methods of passive defense in order to preserve vital, sensitive, and important centers. In this paper, we study the interaction of microwaves with the main components of the earth's surface.
Amir Palham Abbasi
Volume 18, Issue 72 , February 2010, , Pages 28-31
Abstract
The principled use and proper management of arid and semi-arid regions, which cover a significant extent of the Earth’s drylands, require planning based on accurate and timely information on different ecosystem components, including vegetation. Considering vegetation is one of the major and important ...
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The principled use and proper management of arid and semi-arid regions, which cover a significant extent of the Earth’s drylands, require planning based on accurate and timely information on different ecosystem components, including vegetation. Considering vegetation is one of the major and important needs in the management and exploitation of arid and semi-arid regions. Since it is time consuming and costly to collect information at vast levels in dry and desert conditions by traditional ways and through ground operations, the use of new techniques in these studies is necessary. Remote sensing is one of the most effective techniques in this field. The arid and semi-arid regions have low Leaf Area Index and fairly open crowns due to reactions to environmental stresses, which makes the surface soil visible in these areas. The high effect of surface soil on spectral reflections of vegetation in arid and semi-arid regions causes mistakes in evaluating plants in these areas through remote sensing. Many studies have been carried out on introducing suitable plant indices for assessing vegetation changes in arid and semi-arid regions. The results of all these studies indicate that due to variability of vegetation and soil characteristics in different regions of arid and semi-arid regions, as well as differences in utilized satellite data in terms of sensor type, bands number, spectral range, spatial accuracy, etc. it is not possible to introduce a specific indicator for vegetation studies in all arid and semi-arid regions, but, considering the characteristics of vegetation, soil and the type of used satellite data, indicator or indicators that are meaningful according to studies can be introduced for each region. The aim of this study is to investigate the spectral reflections of vegetation in arid and semi-arid regions considering different reactions of plants in arid and semi-arid regions against environmental stresses, the openness of crown of vegetation, and the high effect of surface soil on the reflection of the vegetation in these areas, and to introduce a suitable technique for studying the vegetation of such areas.
Abbas Ali Saleh Abadi (Translator)
Volume 15, Issue 58 , August 2006, , Pages 28-30
Abstract
The technology of hydrographic Side Scan Sonar has been developed by Professor Harold Edgerton and his colleagues in the year 1960. A Side Scan Sonar is a device that has the ability to search the space around it. The Sonar can be compared with a radar, but in a sonar the reflection of sound waves is ...
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The technology of hydrographic Side Scan Sonar has been developed by Professor Harold Edgerton and his colleagues in the year 1960. A Side Scan Sonar is a device that has the ability to search the space around it. The Sonar can be compared with a radar, but in a sonar the reflection of sound waves is used, unlike radar which uses electromagnetic pulses. Sound pulses usually range between 100 and 500 kHz. The frequencies higher than this magnitude have lower ranges, although they increase the accuracy and resolution.
Zoleikha Bagheri (Translator)
Volume 12, Issue 48 , February 2003, , Pages 28-33
Abstract
Earth: The Planet of Water. More than three quarters of the earth's surface is covered by water. Here is a view of the Indian Ocean. The white frozen surface strikes the eyes in the lower part of the globe.The earth, the planet of water, is covered with a thin shell of air that we breathe and protects ...
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Earth: The Planet of Water. More than three quarters of the earth's surface is covered by water. Here is a view of the Indian Ocean. The white frozen surface strikes the eyes in the lower part of the globe.The earth, the planet of water, is covered with a thin shell of air that we breathe and protects us.Chemical factors are responsible for destruction of the thin layer of ozone, which is responsible for protecting humans from ultraviolet rays emitted from the sun.The energy from fossil fuels and destruction of tropical rainforest has caused changes in greenhouse effect of atmosphere, and it can be thought of as the reason the earth is moving toward becoming warmer.All planets are regularly bombed by deadly winds caused by solar energy particles.The dawn is the result of a spectacular light that is created by the sun and a radiance like a cosmic light.
Old magnetic rocks indicate that magnetic poles of the earth have the task of protecting the parts containing electric current, and it is likely that the magnetic field of the earth is already at the peak of a sudden blow. Boston and Italy have been part of the continent of Africa, and a natural glacier covered the Desert. The Pacific eroded the Colorado coastline. These continents were welded together and brought about a row of mountains, thus forming part of the existing oceans.
Seyyed Ali Ebadinejad
Volume 12, Issue 45 , May 2003, , Pages 28-31
Abstract
Geographic Information System (GIS) was introduced for the first time in Canada in the early 1960s, and since then its users increased day by day until it became global in the 1980s.Large institutions, and even small companies whose number of staff do not exceed the number of the two hands’ fingers, ...
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Geographic Information System (GIS) was introduced for the first time in Canada in the early 1960s, and since then its users increased day by day until it became global in the 1980s.Large institutions, and even small companies whose number of staff do not exceed the number of the two hands’ fingers, have established national or global geographic information systems to be able to provide valuable information and data to public and private departments and companies. In this way, they prevent unnecessary repeat of work during collecting data and digitizing maps.Today, most of the papers in this science reflect the results of field experiments and pay less attention to the principles of this science. As a result, it's often observed that experts are very capable at the advanced stage of science but weak at its fundamental stage.
Unlike most data types that are commonly used in new information systems, geographic data is of particular complexity, since these data should include information about location, probable topological connections and recorded characteristics of certain matters. The topological and spatial aspects of the GIS used in design and mapping, and the means of distinguishing between these systems and a new system are among the information that have applications in various fields such as banking, secondary research, booking of airplane tickets and recording medical cases.
Geographic data are connected to certain points of the earth’s surface based on standard coordinate systems. If the subject under study relates only to a limited area, the coordinate system can be purely local, otherwise it may be a visual network at the national or international level, such as the Mercator Coordinate System, which is confirmed by everyone in the field. Geographic data are often recognized as a geographical example of "topics" and phenomena. All geographic studies use phenomenological concepts such as city, river, flood plain, limits of classes of plant species and soil continuity as the main components of the analysis and synthesis of complex information.
Mahdi Mo'meni
Volume 9, Issue 34 , August 2000, , Pages 28-30
Abstract
The Persian Gulf has since distant past been utilized by human being, and its natural conditions have played a major role in this exploitation.In this paper, it has been tried to provide with a brief description of the Persian Gulf conditions and to analyze the role and effect of each factor in sustainable ...
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The Persian Gulf has since distant past been utilized by human being, and its natural conditions have played a major role in this exploitation.In this paper, it has been tried to provide with a brief description of the Persian Gulf conditions and to analyze the role and effect of each factor in sustainable utilization. Finally, proper courses of action for recognition of natural potentials for sustainable exploitation have been presented.
Fatemeh Razi'ee
Volume 7, Issue 28 , February 1998, , Pages 28-34
Abstract
Astronomical reflections are indeed stories of astronomical optical (visible through emitting light) bodies which are extinguished, leaving behind only a nice memory. In this chapter, we deal with a type of telescope-based astronomy which is not possible to practice with naked eyes. It concerns the images ...
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Astronomical reflections are indeed stories of astronomical optical (visible through emitting light) bodies which are extinguished, leaving behind only a nice memory. In this chapter, we deal with a type of telescope-based astronomy which is not possible to practice with naked eyes. It concerns the images of nebulae, a continuous and attractive cloud which indicates the presence of dark objects in space which we are not aware of. First astronomers equipped with telescope observed unclear and expanded objects among the stars which they named nebula (Latin word for dark parts of clouds). Even before telescope, the Andromeda nebula and Magellanic Clouds had been observed by naked eyes as enigmatic permanent spots with a weak light. An example of the most famous and largest nebulae-like or expanded forms is the Milky Way. This galaxy is very ambiguous, and has been a mystery for long. However, these dark and ambiguous shapes in nocturnal sky were gradually classified into two separate parts. These are the same masses which radiate light and heat due to high temperature of atoms that constitute them. The best example of such radiations is the Sun’s ray and other stars and objects formed by stars, such as the Milky Way and other galaxies and spherical star clusters.
Mohammad Hassan Naami
Volume 20, Issue 80 , February 2012, , Pages 29-33
Abstract
The limitations of resources and documents related to the field of space in the country necessitates clarification of the status of space in the development of the country and sustainable security, which, while expressing the fundamental issues concerning space technology and space activities of the ...
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The limitations of resources and documents related to the field of space in the country necessitates clarification of the status of space in the development of the country and sustainable security, which, while expressing the fundamental issues concerning space technology and space activities of the country, examine specialized areas of remote sensing and space imagery. Space structure, space legal regime, space functions and space technology are the major issues addressed in this paper.
Ali Asghar Roshan
Volume 14, Issue 56 , February 2005, , Pages 29-35
Abstract
employment and social situations equal with men, has gradually changed conditions in favor of women. Now women are demanding a larger share of the employment market, and they have achieved significant economic positions in, for example, the emerging electronic industries of newly industrialized Asian ...
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employment and social situations equal with men, has gradually changed conditions in favor of women. Now women are demanding a larger share of the employment market, and they have achieved significant economic positions in, for example, the emerging electronic industries of newly industrialized Asian countries. While in China the sex ratio at the first birth is close to 1, but at next childbirths the proportion of male babies increases, the phenomenon which can be observed in South Korea and Taiwan as well. New techniques for determining gender, an important issue in the Chinese society, include the use of the amniocentesis method in Korea and Taiwan and ultrasound waves in China. The result of the shortage of female babies will lead to the creation in these societies of the largest group of single men in the world unable to get married. According to the latest predictions, by 2020 the number of Chinese single men will be more than the total female population of Taiwan. In addition, an increase in the surplus of male population in China is likely to result, in some areas including Shanghai, in a sharp drop in fertility rates, even to levels under the substitution line.
Hosein Hataminejad
Volume 12, Issue 47 , November 2003, , Pages 29-33
Abstract
The city of Mashhad has long been affected by natural conditions of the region (the existence of suitable farming soil, various mines, etc.) and also by the general state of political economy of the country. "In the third century A.H”, according to Ya’ghubi, “Noghan (the first nucleus ...
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The city of Mashhad has long been affected by natural conditions of the region (the existence of suitable farming soil, various mines, etc.) and also by the general state of political economy of the country. "In the third century A.H”, according to Ya’ghubi, “Noghan (the first nucleus of the city of Mashhad) was a great city renowned for the production of stone dishes”. He refers to Noghan as “the place of turquoise and green marble sale, which was extracted from the surrounding mountains" (Le Strange, 1997: 415). In addition, Moghaddasi in the late third century mentions the markets of the city of Tabran (the current Tus city which is a suburb of Mashhad today), that contained great deal of commodities. (Ibid.) Economic growth in the city of Mashhad begins mainly in the Safavid period. The first Shah of this dynasty, Ismail I, established the Shiite religion as the official religion of the country, and in this situation, attention was paid to the religious cities of the country, especially Mashhad, and the importance of this city continued at the time of his successors (The Encyclopaedia of Islam, 1991, 714).
By reformations of Shah Abbas I Safavid and his efforts to improve and restore roads and build and repair interurban caravansaries and security stations, the trade in the age of Safavids experienced prosperity, and Mashhad, which was highly considered by the Shiite sultans of Safavid religion, was not an exception to this rule (Tahernya, 1997: 175). British businessman George Thompson wrote in 1153 A.H. (at the time of the rule of Nadir Shah Afshar) about the city's economy: “Mashhad is a prosperous city, where commerce plays a significant role. Every day, caravans from Balkh, Badakhshan, Kandahar, India and every corner of Iran's soil enter Mashhad. The large and well-developed markets of this city are brimming with valuable commodities and a large group of merchants from various nations are gathered here” (Afshar Sistani, 1999: 338). He has mentioned the number of caravansaries in this city as almost ninety. (Lockhart, 1366: 136)
Nasrollah Mola'ei Hashjin
Volume 11, Issue 43 , November 2002, , Pages 29-33
Abstract
Geography in its scientific and modern sense is the science of space whose subjects are the natural and human phenomena that create the world and its various places. Accordingly, geography on the one hand describes, examines and analyzes the various phenomena of natural environment in various water, ...
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Geography in its scientific and modern sense is the science of space whose subjects are the natural and human phenomena that create the world and its various places. Accordingly, geography on the one hand describes, examines and analyzes the various phenomena of natural environment in various water, soil, climate and human environment areas as geographical basis, as well as dispersion of social organizations, economic activities and consequences of the interaction of human societies with the environment, and on the other hand it attempts to play an active role in reducing or eliminating spatial inconsistencies and in creation of cultural perspectives through the scientific knowledge that it gains concerning natural rules and social developments.
Alireza Owsati
Volume 9, Issue 33 , May 2000, , Pages 29-34
Abstract
All the stars and celestial bodies are suspended in space due to gravity. The Sun and other bodies in solar system have emerged gradually. Earth is one of the astonishing realities in universe, because it is exactly at the distance (150,000,000 kilometers) from the Sun that, along with the atmosphere ...
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All the stars and celestial bodies are suspended in space due to gravity. The Sun and other bodies in solar system have emerged gradually. Earth is one of the astonishing realities in universe, because it is exactly at the distance (150,000,000 kilometers) from the Sun that, along with the atmosphere which has surrounded it, has made life on this unique planet possible.
Hamid Enayati (Translator)
Volume 8, Issue 30 , August 1999, , Pages 29-35
Abstract
Classification of existing digital photogrammetric systems can not be fitted into a simple model due to their growth and variety. It can be said that they are the end of a vision designed through emergence of high-level, special systems which compete the best analytical systems and are uniquely inexpensive ...
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Classification of existing digital photogrammetric systems can not be fitted into a simple model due to their growth and variety. It can be said that they are the end of a vision designed through emergence of high-level, special systems which compete the best analytical systems and are uniquely inexpensive in comparison with other available developed systems, especially for simple uses. DVP is one of the Softcopy commercial photogrammetric systems which has been examined in a principled manner and its characteristics have been preserved during this examination; so, DVP has indeed grown. This idea indicates the development and direction of a method based on application of a micro-computer, images and a mirror stereoscope. It is a simple method easy to learn by oneself in which presented operation is in an effective and efficient way which is based on decreasing personal coefficient or the principle of equality in topography.Naturally, in new method the digital topographic display has become complex, and has become a conveyor from one stage to another used for three-dimensional measurements. It seems that with this idea and description of microcomputer technology, there is reasonable expectation for advances in new topography in microcomputers. Suitable and simple software and hardware of photogrammetry can create potentials for utilization of photogrammetry experts.
Abbas Khosravi
Volume 6, Issue 21 , May 1997, , Pages 29-34
Abstract
Identification and analysis of natural phenomena and their scientific examination is one of the matters that every researcher in scientific and technical fields must consider. Today, considering development of global communications, establishment of computer systems and expansion of scientific publications, ...
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Identification and analysis of natural phenomena and their scientific examination is one of the matters that every researcher in scientific and technical fields must consider. Today, considering development of global communications, establishment of computer systems and expansion of scientific publications, the knowledge of researchers about the causes of natural phenomena has taken an increasing trend. Interaction of the material forming the earth’s crust with internal and external shape-changing processes creates various landforms whose identification and analysis is one of the main tasks of geomorphologists. Mud volcanos are one of the landforms that attract more attention. This article was written following the observations by author of mud volcanos at an area between Dasht-e Kahir and Tang in Chabahar County in March 1993. It has been tried to review many of the issues concerning these mud volcanos by explanations and pictures.
Volume 1, Issue 2 , February 1990, , Pages 29-29
Abstract
Sepehr will publish, from this issue on, simplegeographic essays for young people and those not familiar with the scince of geography. This will continue in more significant volume if it faces welcoming reactions from readers.
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Sepehr will publish, from this issue on, simplegeographic essays for young people and those not familiar with the scince of geography. This will continue in more significant volume if it faces welcoming reactions from readers.
Gholamhoseyn Salehabadi
Volume 22, SEPEHR , July 2013, , Pages 30-34
Abstract
Jovin plain with an area of 6980 km2 is a syncline between two anticlines of Choghatay elevations in south and Shah Jahan elevations in North. Its main drainage is Kalshur River in Jovin. Because of more than 1110 deep and semi-deep wells being exploited and lack of correct planning in groundwater resources, ...
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Jovin plain with an area of 6980 km2 is a syncline between two anticlines of Choghatay elevations in south and Shah Jahan elevations in North. Its main drainage is Kalshur River in Jovin. Because of more than 1110 deep and semi-deep wells being exploited and lack of correct planning in groundwater resources, this plain have been introduced as a critical areas in Khorasan-e Razavi province. Relatively high density villages, dominance of agricultural activities, industrial factories like Qand-e Jovin and Jamco ferro-chromium, and the fact that two important population centers in the plain (Neqab and Choghatay) have been changed into a town in recent years will definitely result in increasing exploitation of groundwater resources, intensification of ground subsidence and creates new considerations for urban planners. In order to study the relation between ground subsidence and exploitation of groundwater resources, the present article produces and investigates topographic, geologic maps, and satellite imageries and performs field and secondary study. In the next step, piezometric maps of ground water resources were produced using meteorological information and statistics. Ground subsidence zoning map of this plain was produced using GIS techniques. The map indicates that ground subsidence happened mostly in areas where villages have a higher density and population. Moreover, industries in the area were highly influential. Finally based on the geomorphologic maps and zoning of groundwater resources reduction, suggestions are provided regarding feeding of groundwater resources and ground subsidence.
