Remote Sensing (RS)
Kolsoom Shokrilahizadeh; Hamed Naghavi; Morteza Ghobadi; Rahim Maleknia
Abstract
Extended Abstract
Introduction:
Urban green spaces constitute a pivotal component of urban ecosystems, offering a plethora of ecological benefits and services to cities. Augmenting these green patches within urban landscapes and establishing interconnected ecological networks therein represent viable ...
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Extended Abstract
Introduction:
Urban green spaces constitute a pivotal component of urban ecosystems, offering a plethora of ecological benefits and services to cities. Augmenting these green patches within urban landscapes and establishing interconnected ecological networks therein represent viable strategies to mitigate the adverse repercussions of inadequate urban development while bolstering urban environment resilience. In the past few decades, the landscape ecology paradigm has introduced innovative methodologies aimed at comprehending the intricacies of urban green space dynamics and how landscape configurations wield influence over the environmental processes within cities. This research, consequently, sets out with the intention of quantitatively assessing and dissecting the transformations transpiring within Khorramabad's urban green spaces. It does so by harnessing remote sensing data and leveraging landscape metrics to gain deeper insights into the urban landscape's evolution.
Materials & Methods:
The focus of this research centers on Khorramabad city, which serves as the capital of Lorestan province and holds the distinction of being the province's largest city in terms of both population and geographical expanse. Municipally zoned into three distinct regions, the study unfolds across two main phases. Initially, the endeavor involved the creation of comprehensive synoptic maps capturing Khorramabad city's green spaces. This process relied on satellite imagery, followed by a subsequent phase of scrutinizing these maps through the application of landscape metrics.
To execute this, satellite images from various sensors—namely TM, ETM+, and OLI on Landsat 5, 7, and 8 satellites—were harnessed for the years 1987, 2003, and 2019, respectively. These images underwent meticulous preprocessing, culminating in their classification using the maximum likelihood method within the ENVI software environment. To validate the accuracy of the resultant maps, an error matrix was employed. In order to model the quantitative alterations and patterns within Khorramabad's urban green spaces, landscape metrics were harnessed. Notably, the Fragstat software facilitated the analysis of selected landscape metrics, which encompassed four key measures: class area (CA), number of patches (NP), percent of landscape (PLAND), and mean Euclidean nearest neighbor distance (ENN-MN).
Results:
The analysis of spatial-temporal changes in Khorramabad city's green spaces reveals an evident declining trend in their overall pattern. The outcomes underscore a substantial reduction both in the quantity of green patches and the area they encompass, dwindling from 703.8 hectares in 1987 to 629.88 hectares in 2019. Additionally, the investigation into landscape metrics' composition and distribution underscores an absence of cohesive dispersion on the city-wide scale. Within Khorramabad city, regions 1 and 3 exhibit inadequate green space composition and distribution. The computed metric for Class Area (CA) reflects a decrease from 195.66 hectares in 1987 to 191.63 hectares in 2003, further diminishing to 170.145 hectares by 2019. Correspondingly, the metric for Number of Patches (NP) indicates the lowest count of patches (33) in 1987, which escalated to 122 patches in 2003, and ultimately reaching 183 patches by 2019. Moreover, Proportion of Landscape (PLAND) data highlights that regions 3 and 2 demonstrate the highest (19.45%) and lowest (7.18%) green area proportions, respectively. Notably, the PLAND metric underwent modification from 229.81 meters in 1987 to 88.47 meters in 2003, further diminishing to 78.65 meters in 2019. The findings underscore deficiencies in Khorramabad city's urban green spaces, indicating a lack of favorable conditions for their development.
Conclusion:
The research conducted an assessment of urban green spaces within the urban areas of Khorramabad, utilizing remote sensing data and landscape metrics. The findings indicated a consistent downward trend in the overall extent of green spaces in Khorramabad city over various years. The distribution of green patches within the city was deemed relatively inappropriate, lacking an optimal arrangement. To enhance the status of green spaces, there is a need to establish continuity between discrete green patches and smaller green areas. This study underscores the significance of prioritizing sustainable management for Khorramabad's urban green space, aiming to prevent its degradation. The study's limitation lies in its reliance on medium-resolution Landsat image data. Overcoming this constraint through the incorporation of high-resolution data holds promise, particularly for fragmented green spaces in urban areas.
Hekmatollah Mohammad Khanlu; Mahdi Modiri; Elahe Khesali; Hamid Enayati
Abstract
Introduction
Hydrography is a science used for regular measurement of parameters such as depth of water, geophysical geology, tide, water flow, waves and other physical properties of seawater. It is also used for the production of maritime maps. Hydrography contributes significantly to the internal ...
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Introduction
Hydrography is a science used for regular measurement of parameters such as depth of water, geophysical geology, tide, water flow, waves and other physical properties of seawater. It is also used for the production of maritime maps. Hydrography contributes significantly to the internal infrastructure of coastal countries. Providing proper hydrographic services ensures safe and efficient sailing. Thus, development of hydrographic services on the national level can improve safety of mariners, and protect people’s lives and belongings on the sea, while providing some facilities for the protection of marine environment. The advancement of space technologies in recent years has increased the speed of spatial information production and facilitated sea monitoring.
Materials and Methods
Different methods are used for bathymetry. Lyzanga et al (1978) used a linear combination of the logarithm of corrected radiance ratio. This method is based on the simplification of Beer's physical model in which a linear equation of five unknowns is obtained for two bands. In 2006, Lyzanga et al. presented an improved version of their model. Using Tow-Bands Reflection Ratio, Stampf et al (2003) not only reduced the number of unknown variables in Lyzenga method, but also decreased the sensitivity of depth determination to different substrates. In this method, the difference between absorption properties of green and blue bands is used. TCarta is a global supplier of geospatial products. The company generated Satellite Derived Bathymetry (SDB) dataset by accurately extracting water depth from multispectral imageries received from the European Space Agency’s Sentinel-2 Satellite. The resulting bathymetric data had a point spacing of 10 meters, while measuring up to a depth of 15 meters. Data covered a 30-square kilometer area around Preparis Island on the Bay of Bengal.
The present article used images received from Sentinel-2 in 7 different periods for depth determination, and 1: 25,000 ADMIRALTY Nautical Charts for accuracy evaluation. Following the assessment of water transparency in received images, the 12/15/2018 image was used for depth determination. Case study area contains around 130 km along the Port of Salalah, Oman.
Results and Discussion
In order to implement the model, it is necessary to separate land from water in images using NDVI, NDWI, MNDWI and AWEI indices. The NDVI index has been used in this project. NDVI is primarily used to estimate vegetation cover, but since this index exhibits a negative value in areas covered with water, this property is used to provide a mask for separating land from water. In this step, 68 control points and 68 check points were selected from the existing ADMIRALTY map. The DN values of the corresponding pixels of the selected points were extracted from four 10-meter bands of Sentinel-2 images. The control and checkpoints and the DN value of their corresponding pixels were extracted in 4 separate files, then these 4 files were logged into the Bathymetry software and the parameters of LMR and Stumpf methods were calculated. The root mean square error (RMSE) and correlation coefficient (CC) were used to assess geometric accuracy. In order to extract necessary parameters for each model, RMSE= 2.15 m and CC= 92.5% were calculated at depth distances of 0 to 20m. Results indicates higher accuracy and stronger correlation of LMR findings. Therefore, this method was used for depth determination between 0 to 20 meters. The 5 parameters extracted from the Bathymetry software and the corresponding pixel values of the four bands with 10-meter resolution extracted from the Sentinel-2 image (received from the on 12-15-2018) were used as input. Linear Regression Model was applied to transform 4 bands of Sentinel-2 image into depth. The output of the model (depth) was presented as the Substrate DEM of the coasts of Port of Salaleh, Oman.
Conclusion
Hence, it can be concluded that Remote Sensing technologies can be used for depth determination and sea monitoring at critical times (during wars or other periods of insecurity) for an acceptable time period. It also provides an appropriate context for bathymetry of inaccessible coastlines and monitoring of strategic widespread water zones. In this way, the depth of sea bed in shallow areas is extracted using spectral analysis of satellite data and different models.
Saeideh Zamani; Majid Rahimzadegan
Abstract
Extended Abstract Introduction Evaporation from the lakes behind the dams and freshwater lakes is one of the most important parameters in water resource losses. Therefore, zoning evaporation is very important in water resources management. There are various methods for measuring and estimating evapotranspiration ...
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Extended Abstract Introduction Evaporation from the lakes behind the dams and freshwater lakes is one of the most important parameters in water resource losses. Therefore, zoning evaporation is very important in water resources management. There are various methods for measuring and estimating evapotranspiration (ET) that are used according to their accuracy and cost. These models include using evaporation pan and using meteorological models such as Bowen ratio and eddy correlation methods. Nowadays, modern methods such as utilizing satellite remote sensing images are developed to estimate evapotranspiration in different regions. Surface Energy Balance Algorithm for Land (SEBAL) is one of these algorithms which is highly regarded. SEBAL estimates ET as a residual in energy flux in the surface of land. This is done by calculating the difference in the soil heat flux and the sensible heat flux from the net radiation. Material and Methods Initially, SEBAL was extensively used for mapping evapotranspiration in lands and vegetation cover such as crop field, but it was rarely used to estimate evaporation from water bodies, especially freshwater bodies. The aim of this study was to use SEBAL algorithm to map evaporation from freshwater of dam lakes. In this regard, three Landsat Thematic Mapper images (TM) acquired in May 29th, July 9th, and August 1st, 2011 were provided from Amir Kabir (Karaj) dam and the downstream agricultural lands. The selected area is located between two provinces of Tehran and Karaj. Amir Kabir dam supplies a part of drinking and agriculture water for these two provinces. To implement SEBAL method, radiometric and geometric corrections were performed and image bands were converted to radiance and reflectance values according to their wavelengths. In order to prepare required parameters of SEBAL, meteorological data measured by Karaj meteorological station at the selected dates were provided. These data included elevation of meteorological station, daily solar radiation, dew point temperature, wind speed, and air temperature. Furthermore, the evaporation values recorded by Tehran Regional Water Authority located at the southwestern part of the dam using evaporation pan were used as ground truth data which measurements and were performed in related dates. All of the implementations of this research were accomplished using the ENVI 5.1, Excel 2007, Ref ET, and MATLAB R2012a software. The instantaneous ET at the time of satellite overpass was calculated calculate using SEBAL method and in order to calculate the daily ET, the calculation of the reference ET was necessary. To compute reference ET in this research, Ref ET software developed in Idaho University was utilized. One of the required data in the Ref ET software is hourly solar radiation. Because of the lack of hourly solar radiation data in the selected meteorological stations, angstrom method was used. Then, the ratio of instantaneous ET to reference ET was used to calculate the 24 hour ET. Results and Discussion In each stage of SEBAL method, its components, such as Normalized Difference Vegetation Index (NDVI), and Land Surface Temperature (LST) were checked to prevent the undesired errors. After performing implementations, the results showed that the absolute difference values of evaporation acquired from SEBAL method and ground truth data were 0.2, 0.2, and 0.3, in selected days, respectively, which leads to the Root Mean Square Value (RMSE) of 0.27 mm that is an acceptable value. Moreover, the total evaporation values from the entire dam surface for selected days were 8.037, 10.634, and 5.435 meters per day, respectively, which were significant values. The acquired map of evaporation from dam lake surface illustrated that the value of evaporation was increasing from coastal areas to deep regions. This was proved in the same researches. The values changed from 0.5 mm in the shoreline to 3.5 mm in deep water. One of the uncertainty sources of this research was the use of daily solar radiation due to the lack of meteorological data and computing hourly values by using Angstrom method. Another uncertainty source is utilizing empirical relations such as relation of estimating atmospheric transmissivity, and narrow band emissivity and broad band emissivity which is better to calibrate before use. Another shortage of SEBAL method which can lead to uncertainty is empirical process of selecting cold and hot pixels which are used to estimate air temperature and soil temperature, respectively. Conclusion Despite the mentioned shortages of SEBAL method, the results showed the applicability of SEBAL method to mapping and estimating evaporation from freshwater lakes and dam lakes as an accurate and inexpensive method. Furthermore, the evaporation from freshwater lake surface was calculated using SEBAL model which were significant values in selected days and proved the requirement for protective operations.
Mohammad Rahim Rahnama; Mohammad Ajza Shokouhi; behnam ata
Abstract
Extended abstract Introduction Cities are always influenced by various forces and factors. They are transformed by social changes, demographic displacements, economic changes, and technological innovations. As the population grows, activities and investments are greatly expanded and the ...
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Extended abstract Introduction Cities are always influenced by various forces and factors. They are transformed by social changes, demographic displacements, economic changes, and technological innovations. As the population grows, activities and investments are greatly expanded and the physical system of the cities undergoes fundamental changes.Along with the rapid urbanization process, a large amount of natural lands, such as forests and wetlands, has turned into agricultural land and residential areas. Quick land use changes have had profound effects on natural and human environments. For example, agricultural developments and structures lead to deforestation, soil erosion, water basin degradation, and biodiversity loss and pollution. In addition, changes in the use of agricultural land and the acceleration of urbanization have led to an increase in impenetrable levels, which has led to the development of a transport network and the accumulation of non-disturbing contaminations associated with surface runoff. Due to these great effects, the detection and anticipation of land use changes has become an important topic in environmental management and land use planning. At their initial stagesof formation, most of the cities in Iran were established near or in the middle of thehigh-quality agricultural lands with the purpose of using high-quality soil foragriculture and then, these lands were gradually buried under the cities throughdevelopment of villages and changing into cities and then development of thecities. Accordingly agricultural activities were inevitably receded to the poorlands. Materials & Methods To access fundamental maps for analysis of data and use of different methods to achieve the goal of this study, satellite images related to the years 1987,2000 and 2010 are used. Topographic maps of 1:50000 scales obtained from the army geographical organization are used for geometric correction. At this stage, geometric correction was performed on the images using image sensor TM of the year 2010 image-vector, which were geo-referenced. To perform this task, 42ground control points with appropriate distribution in road junctions, water channels, etc. were used. In this research, to process data, make models, and analyze the output, land cover maps produced in the years 1987 and 2014 as inputs of the LCM model, were selected to analyze the changes in the region and predict land use changes in the year 1404. The LCM model requires two maps covering lands belonging to different times as inputs. In this study, Gains and losses, net changes, unchanged regions, transitions from each user to another in different classes of land cover, were mapped to the model analysis section of the model.ENVI, IDRISI Selva and ARCGIS10 were used to categorize the uses of most-probability-models and methods and finally Ca_Markov model was used to predict and calculate changes in 2025, 2035 and 2045. Results & Discussion Multi-temporal images used in this study were used in mapping land coverafter geometric corrections. With regard to existing images and maps and the condition of the area under investigation and field visit for mapping land cover, five types of applications are discovered for land namely, residential lands,irrigated lands, rain-fed lands, sterile lands, parks and gardens. Altogether, during this time (27years), agricultural and residential land cover has increased and sterile land and rain-fed land cover has decreased. Agricultural lands consume a huge amount of water due to exploiting water from deep holes and land overuse that has turned rain-fed lands and sterile lands into water-fed and residential lands. As the table of predicting areas indicates, the greatest increase of about 1744/74 hectares belongs to agricultural lands and 1741/79 hectares belong to the urban lands which includes: residential lands, trade centers, military areas, hospitals, higher education institutes, etc. The least change which is 274/18 hectares, belong to parks and gardens in and around the cities. The most decline of 2261/59 hectares, is observed in sterile lands. Of the total net changes, one can conclude that urban use has increased and all land cover has become largely urbanized, as well as water lands with the rise and development of deep wells. The need to preserve these lands from the physical development of the city in this direction is essential in order to develop the sustainable development of the city. There are many undeveloped lands in the old days due to the lack of water and the lack of facilities. The advancement of agriculture, turned these lands into agricultural lands. Today, landless areas are mostly on the suburbs or around the cities. This is mainly because of the farmers who leave their lands in a state of desert in hope of urban development to gain huge profits.This is the case where the city of Gonbad-e-Kavoos is not an exception to this rule. Parks and Gardens also have a rational increase in the city, therefore, in urban development projects, parks have been created but the size of the gardens is very low in the city of Gonbad-e-Kavoos. By predicting the changes in usages, it is concluded that the most changes will take place in urban usages and rain-fed and sterile lands with dramatic increase and decrease respectively.As the population of the city of Gonbad- e-Kavoosgrows, some steps should be taken to develop the spatial area of the city so as to prevent the destruction of fertile lands for the sake of human construction. Conclusion In this study, the effect of physical expansion of Gonbad-e-Kavoos city on agricultural lands is investigated. Findings indicate that during 45 years, around 1880 hectares of fertile farmlands surrounding the city are destroyed. The main reason behind this destruction is the horizontal expansion of the city. Hence, one of the fundamental bases of sustainable urban development is the increase of city density. It is concluded that horizontal expansion of the city is totally in contradiction to sustainable development and it leads to more instability of the city.
sina saber mahani; Mohammadreza Sepahvand
Abstract
Extended Abstract
Since Iran is located on the Alpine-Himalayan seismicbelt and it has high seismicity, study of earthquake seismologyis necessary. Part of alpine-Himalayan seismic belt is Iranplateau that demonstrates high seismicity behavior and it has uniquedeformation.
Seismotectonic studies indicate ...
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Extended Abstract
Since Iran is located on the Alpine-Himalayan seismicbelt and it has high seismicity, study of earthquake seismologyis necessary. Part of alpine-Himalayan seismic belt is Iranplateau that demonstrates high seismicity behavior and it has uniquedeformation.
Seismotectonic studies indicate a high density of active fault existencein this plateau. In all of Iran seismotectonic regime, eastof Iran seismotectonic zone due to the presence of strike slipfault system and occurrence of large earthquakes has a greatimportance. Destructive earthquakes such as 6.6Mw Bam (2006)and 6.7 MwRigan (2010) revealed high potential of earthquakeoccurrence. Intended area in this study is Rigan that is located in Kerman province in Iran. This area has important faults such as Kahurak, Bam, Nosratabad, Shahdad, Guk, Golbaf, Sirch and Sabzevaran which have high seismicity.
In this paper, we consideredcloud formation as earthquake precursor for Mohammad Abad-Rigan’s earthquake (2011) that is known less. Thermal precursor was also consideredin this study. According to the existing theories, Rises in stresscan produce initial fracture in the region. Therefore, with the rise intemperature, water evaporation in the pores of stone is created. Whenvapor has appropriate condition (for example; lower temperature and existingenough water), it convert to clouds. One of the fantastic features of this phenomenon is that, these clouds cannot move in the presence of wind, Because of the steady source of their generations. This fact is a distinguishable thing for recognizing thiscloud among other clouds. In the first part, panchromatic images of62days before the event were taken and then theserow images were geo-referenced. Thus, earthquake clouds were digitally extracted andthe results were superposed on the topographic map of the intended region. It should also be mentioned that earthquake clouds were detected 10 days priorto the earthquake (January 17th).A period of 10 days is a suitabletime for making decisions in decision making organizations such as, Governorates, Municipalities, etc. Verdict basedon earthquake clouds is not enough for a good conclusion about earthquake occurring, and it is necessarythat we apply other precursors and pre-indicators, one of which is thermalinfrared that has great results.
In another part of the study, temperature content of thermal bands (bands 31 and 32) ofMODIS is extracted and Land Surface Temperature (LST) time serieswere created. Temperature variations are always considered as animportant and effective factor in earthquake phenomenon studying. Thermal anomalycan be seen within 1-24 days before earthquake and thetemperature increases 5 to12 degrees and then return to the previousmode after the earthquake. Some other researchers presented the increaseof 2 to 10 degrees. The idea that earthquake may be interrelated withtemperature was proved by applying it in Russia, China and Japan. However, notice that thermal anomaly may occur due to otherreasons except earthquake. When it is because of earthquake, actuallyit is because of the stress existing in the underground layersand changes in soil properties. Zuji et al. (1990) provedthat gases such as methane, carbon dioxide and hydrogen are releasedfrom soil cracks before earthquake which lead to intensification ofchlorofluorocarbons (CFC) and magnetic fields of the earth. There aresome other theories about this phenomenon such as piezoelectric andexpansion forces of the elastic strain that increase temperature.
Aftergetting images from NASA website and preprocessing them by deduction ofAir temperature time series from LST time series, atmospheric effectsthat exist because of the weather condition is eliminated. Obtainedsignal was some noisy. In the next step, the waveletas a powerful filter is applied to time series. Forextracting Interpretable results, Statistical test such as standard deviation mustbe perform on filtered time series. Standard deviation (ST) cancreate normal limited area. By using limited area that producedby ST, thermal anomaly is detected 2 days prior tothe earthquake. Also, with colorization of thermal images and then creationof visual time series, strike of fault line is found.
Finally, by Comparingthe earthquake cloud line, focal mechanismandhigh temperature zone, high correlation was found. These results showthe observed cloud related to Rigan’s earthquake and also showthe high temperature zone related to earthquake event.
Resultsof this study can be used in two aspects, oneof which is the application in early warning system and the otheris the application in geology usage. Second usage helps geophysicist andgeologist to detect hidden and caused fault.
Saleh Arekhi
Abstract
The face of the earth is always changing due to human activities and natural phenomena. Therefore, in order to optimize the management of the natural areas, knowledge of the ratio of land cover / land use changes is considered necessary.The present study was conducted to detect changes in land cover/land ...
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The face of the earth is always changing due to human activities and natural phenomena. Therefore, in order to optimize the management of the natural areas, knowledge of the ratio of land cover / land use changes is considered necessary.The present study was conducted to detect changes in land cover/land use in Abdanan region over a period of 25 years. In order to carry out the research, images of the years of 1985, 2000 and 2010 from TM, ETM + and TM sensors of Landsat satellite were used, and the map of the change detection was prepared and the final results was presented after performing the necessary corrections in the preprocessing stage, by the object-oriented classification of the images in the IdrisiSelvi software environment.The results show that during the period from 1985 to 2010, we are witnessing the decreasing trend of lands with moderate and good rangeland cover, which indicates the general trend of destruction in the region through the replacement of moderate and good pastures by the uses of poor pasture and barren lands. The extracted coefficients of validity assessment (total accuracy and kappa coefficient of 95% and 94% respectively) indicate the high accuracy of this classification method.
According to the results obtained from this research, it is suggested that the object-oriented classification method to be used in the preparation of land cover / land use maps and also the detection of changes.
Mohammad Nasrollahi; Maryam Mombeni; Sara Valizadeh; Hasan Khosravi
Abstract
Oneof the direct methods of land use impacts on thehydrological conditions of each region is the relation between landuse changes and the groundwater table fluctuations that can assistmanagers in optimal management of natural resources. In thisstudy, to evaluate the impacts of land use changes on thegroundwater ...
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Oneof the direct methods of land use impacts on thehydrological conditions of each region is the relation between landuse changes and the groundwater table fluctuations that can assistmanagers in optimal management of natural resources. In thisstudy, to evaluate the impacts of land use changes on thegroundwater level drops in Gilan-E gharb plain, satellite imagesfrom MSS, TM and ETM sensors in 1985, 2000, 2010 were used. Afterprocessing and analysis of images, the region were classified intosix classes in terms of land use including forest, pasture, dry and water farming, farming, and residential areas. Quantitative statistics of piezometric wells in the plain during1999 -2010was used to examinethe aquifer changes and the resulting layerswere also classified. The results showed that pasture land useholds the largest area with more than 50% of the maximum area, so thatit formed 61.8% (9927 ha) and 67.15% (10782 ha) of the area in1985and 2000 respectively. Its area has decreased during the period from2000 -2010,so thatit has covered 50.23% (8066 ha) of the region in 2010. Evaluation of dry andwater farming also showed that it has facedan area reduction of 0.84% (130 ha) during1985-2000,but these changes in the period of 2000 to 2010 has increased to 1429ha which formed 8.9% of the region. Investigating the rate of groundwater dropsshowed that ground water drop has increased by replacing the pasture land use class with water and dry farming classes.These changes have caused 83.93% ofthe area to have a groundwater drop of more than 50 cmper year in 2010, so that the area of this region has been43.85% of the regionin 2000. Human intervention is undoubtedly one of the most important factors ofthe region destruction.
Vahed Kiani; Jahangir Feghhi; Aliakbar Nazari Samani; Afshin Alizadeh Shabani
Volume 22, Issue 87 , November 2013, , Pages 29-31
Abstract
Multispectral remote sensing data is an important informational resource used for recognizing surface changes. To the extent that today, remote sensing images can provide the latest information on vegetation and land use. The present study seeks to detect changes in vegetation and land use across Taleqan ...
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Multispectral remote sensing data is an important informational resource used for recognizing surface changes. To the extent that today, remote sensing images can provide the latest information on vegetation and land use. The present study seeks to detect changes in vegetation and land use across Taleqan area in time period between 1988 and 2007 using remote sensing. Taleqan is located in Alborz province (Karaj) and Taleqan basin. Results indicate that area dedicated to gardening has increased to 2.28 percent, while agricultural lands have faced a 15.05 decrease. On the other hand, rangelands have decreased to 16.25 percent and bare lands have increased to 28.08 percent. The most important change happened with the construction of Taleqan storage dam in 1999 which submerged more than 1100 hectares of the most desirable lands in the area. Since bare lands have increased and rangelands have decreased, thus from an ecological viewpoint it is possible to say that vegetation is degrading. Therefore, in order to restore bare lands, performing rangeland plans and avoiding unplanned changes can be suggested.
Ali Shojaeean
Volume 22, Issue 86 , June 2013, , Pages 55-62
Abstract
Detection of changes in landuse, including the use of multi-time data set to determine the areas where have been had landuse and land cover change detection in various dates. Applying of remote sensing as a repeatable, commodious and available instrument is one of the newest method ...
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Detection of changes in landuse, including the use of multi-time data set to determine the areas where have been had landuse and land cover change detection in various dates. Applying of remote sensing as a repeatable, commodious and available instrument is one of the newest method in this context. The images are used in this research received from the Landsat sattelite and its ETM sensor in order to investigate landuse changes in Dezful area with special attention to changes in agricultural land between 2002 and 2010. After preprocessing the images and classification to product two Landsue maps of two dates, each of them are collected in grades nine categories and also each landuse class is assigned a code of 1 to 9. In order to compare the nine landuse classes from 2002 to 2010 the LMM )Lanuse Multiplcation Matrix(model is used. Using the matrix elements, as a result of multiplying older landuse map to number by 10 and then sum that to recent map, the conversion rate of landuses to others are determined. The results indicate that in some areas have been converted to agricultural land in favor, but the total area of irrigated agricultural lands are decreasing. The greatest reduction of agricultural land was to wasteland with 3857 hectares. In the next place, there is the waterway with of 2238 hectares.
Shahab Sherafati; Manuchehr Masumi
Volume 21, Issue 84 , February 2013, , Pages 145-156
Abstract
Lots of parameters like growing of plants, trees falling across power line, land sliding and flood may lead to massive damage of power line corridors. Therefore, several methods have been used for monitoring and inspecting power lines including field surveying, aerial image analysis and LIDAR analysis ...
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Lots of parameters like growing of plants, trees falling across power line, land sliding and flood may lead to massive damage of power line corridors. Therefore, several methods have been used for monitoring and inspecting power lines including field surveying, aerial image analysis and LIDAR analysis which are very time consuming and expensive. Implimantation of satellite images and remote sensing technology may be an alternative method. But this new method too, may have some limitations in analyzing small features. In this paper, the main objective is to discuss satellite images capabilities in automatic pylon extraction and finding power lines. For this purpose, IRS-P5 satellite images have been used as the main data. This sensor provides panchromatic images with spatial resolution of 2.5 meter. In contrast with some high spatial resolution sensors like WorldviewII and GeoEyeI that provides multispectral images with better spatial and spectral resolution (about 1.6m in multispectral bands and 0.5m in panchromatic band), it is more troublesome to extract pylons in P5 images. Indeed, these sensors can show a pylon and its shadow like two separate triangles, but in P5 images pylons are like dark speckels. Therefore, in this paper several conditions have been used to distinguish pylons and power lines correctly. Results show that the proposed method can satisfactorily extract pylons in homogeneous areas, but in rough regins that have lots of small dark speckles (like vegetation areas), the accuracy decreases. As the second objective of this paper, the capability of satellite images in measuring pylons’ height has been discussed. P5 stereo images can not find the height of the pylons, but sensors with higher spatial resolution, like Worldview I, have this capability. Although, even in this sensors, reaching stereo images matching pylons’ pixel may be a challenging task.
Siamak Taghizadeh ghaleh jooghi; Manuchehr Masumi
Volume 21, SEPEHR , February 2013, , Pages 59-65
Abstract
Land forms are always changing because of human activities and natural phenomena. In urban environment, these changes happen with more diversity and speed. As a result, understanding land use changes is essential for optimal urban management. Thus, accessing information regarding land use and its changes ...
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Land forms are always changing because of human activities and natural phenomena. In urban environment, these changes happen with more diversity and speed. As a result, understanding land use changes is essential for optimal urban management. Thus, accessing information regarding land use and its changes over time are among important issues in urban management. Population growth and overusing the earth potential have increased the pressure on environment. Therefore, controlling the trend of urban development is necessary.
Using the new and precise tool of GIS and RS sciences and techniques, satellite images and aerial photos, scholars, researchers and planners can investigate and study environmental and physical changes of the city in different time periods, exploit and analyze data, control and predict urban development trend.
In order to determine level of land use changes in Naqade during 1964-1999, the present article investigate and analyze aerial photos and satellite images in different land uses and land covers in five different classes like residential classes, roads, vegetation, jungles, and surface water. Results were determined and digitalized in different layers for the sake of comparing and analyzing the changes.
Parviz Abdi
Volume 14, Issue 54 , August 2005, , Pages 36-41
Abstract
Since Quaternary organizations form the basis of human society's life, the Quaternary study is the study of the enormous and potential natural reserves of each country, which should be the study-basis of sustainable development. High-resolution satellite digital images with different wavelengths, along ...
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Since Quaternary organizations form the basis of human society's life, the Quaternary study is the study of the enormous and potential natural reserves of each country, which should be the study-basis of sustainable development. High-resolution satellite digital images with different wavelengths, along with utilization of GIS systems and special data processing software, have provided commentators with the possibility to study various issues related to natural resources with very high accuracy and speed. Accordingly, in this paper, using ETM Landsat satellite images, a method for the preparation of Quaternary alluvial maps has been proposed. In order to carry out this research, after collecting required data and ETM Landsat satellite images, these data were processed and a Quaternary map was prepared in the GIS program environment. By summing up the results, we can say that from a combination of 6 bands (bands 1, 2, 3, 4, 5 and 7) out of the seven information bands of ETM in the range of visible to thermal near-infrared wavelengths, different color composites for the purpose of separation of lithological units were fabricated, the best of which being a combination of three bands of 5, 3 and 1. In this image, various lithological units are well separated, and by carrying out the necessary examinations, its accuracy was estimated to be about 90%, which indicates a very satisfactory coefficient of reliability. Using the results of these studies, we can identify and exploit the potentials of this system according to their visual characteristics.
Ali Abdi
Volume 14, Issue 56 , February 2005, , Pages 9-15
Abstract
Decrease in production capacity of soils is one of the problems in the country. This decrease is affected by factors such as soil erosion, especially surface erosion. Exit of more than 2 billion tons of sediment per year from the watersheds of the country shows the depth of the disaster. Among other ...
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Decrease in production capacity of soils is one of the problems in the country. This decrease is affected by factors such as soil erosion, especially surface erosion. Exit of more than 2 billion tons of sediment per year from the watersheds of the country shows the depth of the disaster. Among other factors that play a major role in reducing the fertility of soils is the salinity of land. This phenomenon occurs in natural resources (low lands) and agricultural lands (inappropriate drainage and improper management). Preparation of soil salinity map is one of the first steps in identifying these areas. There are several methods that can be used to achieve this goal. One of these methods is the application of satellite imagery and spectral reflections in order to provide a map of salinity in different regions of the country, because these images are completely new and up-to-date and display the latest changes on the Earth's surface. In this paper, which is the result of implementation of research project, the application of satellite imagery in preparation of Qazvin plain salinity map using satellite images of Landsat ETM in 2000 and Landsat TM in 1987 in a spectrophotometric manner was investigated. Comparison of the obtained results with experimental data of soil samples and field observations confirms the high accuracy (83.3%) of the prepared Qazvin salinity map by the spectral method.
