Mahdi Modiri
Volume 11, Issue 41 , May 2002, , Pages 2-5
Abstract
Video recording is a form and state of electronic image recording in which standard analogue television signals are recorded on a magnetic tape or disk. Cameras used for video recording of aerial images include: single-band, multi-band or multi-single-band cameras. These cameras can read visible wavelengths, ...
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Video recording is a form and state of electronic image recording in which standard analogue television signals are recorded on a magnetic tape or disk. Cameras used for video recording of aerial images include: single-band, multi-band or multi-single-band cameras. These cameras can read visible wavelengths, near-infrared, and half-infrared (not all cameras cover this full range). For example, figure (1) shows a multi-band video camera that is sensitive to green, red and near-infrared wavelengths, and models the spectral response of colored infrared images.
Mahdi Modiri
Volume 10, Issue 40 , February 2001, , Pages 2-6
Abstract
The images are formed through the change in the strength of brightness of the scene upon the film. At first glance, in aerial photography such changes are related only to the change in the type of the land feature. Of course, this hypothesis is an over-simplification of the issue, because there are many ...
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The images are formed through the change in the strength of brightness of the scene upon the film. At first glance, in aerial photography such changes are related only to the change in the type of the land feature. Of course, this hypothesis is an over-simplification of the issue, because there are many factors that are not related to the type or conditions of a land feature and can affect the measurements of the exposure value of the film. Since the above-mentioned factors affect the measurement of exposure but do not play a role in the true changes of the type of land cover due to conditions, they are called "external effects". Here, the major geometric effects that affect the exposure of the film are discussed.
Mahdi Modiri
Volume 10, Issue 39 , November 2001, , Pages 2-5
Abstract
Graphics such as maps, aerial photos and satellite images have become an integral part of the web. One of the reasons for this is reducing the cost of distribution and presentation, because putting color graphics on the web is much cheaper than color printing on paper. When we consider the extra shipping ...
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Graphics such as maps, aerial photos and satellite images have become an integral part of the web. One of the reasons for this is reducing the cost of distribution and presentation, because putting color graphics on the web is much cheaper than color printing on paper. When we consider the extra shipping and distribution costs for print products, we will realize that distributing maps and images over the Internet is cost-effective. However, printing maps has advantages that cannot be ignored, including very suitable print resolution (the high resolution print has a resolution of 1200 to 3400 dots per inch or 472 to 1339 dots per centimeter). On the other hand, computer screen can only have a precision of 65 to 120 dpi (25.6 to 47.2 dots per centimeter). Computer screen has limitations in terms of screen dimensions: the standard screen size ranges from 14 inches to 21 inches, while maps, photos and prints can be made at much larger cuts.
Mahdi Modiri
Volume 10, Issue 38 , August 2001, , Pages 2-7
Abstract
Currently, there are many computer sites that make maps accessible to users all over the world. The main reasons for their increasing expansion are:• Reduction of cost (distribution of color graphics such as maps by computer sites costs far less than printing and distributing maps on paper)• ...
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Currently, there are many computer sites that make maps accessible to users all over the world. The main reasons for their increasing expansion are:• Reduction of cost (distribution of color graphics such as maps by computer sites costs far less than printing and distributing maps on paper)• Reduction of transmission time (maps that are put on computer networks can be transmitted over a short period of time (not exceeding a few seconds) to users anywhere in the world)• Enhancing abilities (it makes interaction between GIS and users possible, so that full conversational conditions are achieved.)• Extensive use (Computer map provides users with a wide range of applications for maps)• GIS (Cartographic Information System provides basic information and topological structure of various data in the GIS “Geographic Information System”).
Mahdi Modiri
Volume 10, Issue 37 , May 2001, , Pages 2-16
Abstract
Today there is rarely any applied science or branch of activity on earth that has no need to understanding the environment, geographic position and natural conditions and potentials. Geographic information is the most important decision-making tool in different activities on earth.The knowledge of mapping ...
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Today there is rarely any applied science or branch of activity on earth that has no need to understanding the environment, geographic position and natural conditions and potentials. Geographic information is the most important decision-making tool in different activities on earth.The knowledge of mapping (surveying, remote sensing, and geographic engineering) has benefited from the blessings of the glorious Islamic Revolution more than any other science. The dramatic changes and advances that have been made in earth sciences in recent years have been influenced by the need for quick and accurate access to better understanding of the land and potentials of the country in the field of defense and developmental construction.
Mahdi Modiri
Volume 9, Issue 36 , February 2000, , Pages 2-8
Abstract
Aerial photography can be carried out by any type of camera. Many of the utilized aerial photos are taken from a lightweight aircraft by thirty-five-mm cameras. Simplicity and low cost of taking photographs by thirty-five-mm cameras, especially for analyzing small areas, has made them an ideal sensor ...
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Aerial photography can be carried out by any type of camera. Many of the utilized aerial photos are taken from a lightweight aircraft by thirty-five-mm cameras. Simplicity and low cost of taking photographs by thirty-five-mm cameras, especially for analyzing small areas, has made them an ideal sensor (the actual size of the images taken by this system is 36 * 24 mm2). In some cases, seventy-millimeter cameras are also used (the actual size of images by such systems is 55 * 55mm2). On the whole, in most cases of aerial photography a camera is used that has a suitable precision. These cameras are designed to allow for taking a large number of photos in rapid succession with geometric homogeneity.
Currently more than one hundred different types of cameras are used that can be categorized into one of four main categories:1- Single-frame cameras2 – Cameras with multi-lens frames3. Strip cameras4 - Panoramic cameras
Mahdi Modiri
Volume 9, Issue 35 , November 2000, , Pages 2-3
Abstract
Photography is one of the main means of transmission of information and collection of geographic data with wide applications, and aerial photography and remote sensing are the most common ways of quick access to geographic information remotely.
- Better understanding of land by viewing and interpreting ...
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Photography is one of the main means of transmission of information and collection of geographic data with wide applications, and aerial photography and remote sensing are the most common ways of quick access to geographic information remotely.
- Better understanding of land by viewing and interpreting aerial and space images; - Identification of natural and artificial phenomena and features and their geometric measurement; - Introduction of geographic factors of the formation, development and expansion of cities; - and the production of aerial photos and their conversion into topographic and thematic maps are among the applications of aerial photography in the earth sciences, especially surveying and geography. Aerial photography is the most economical way to access geographic information remotely. Aerial photography, due to its many advantages, is one of the most efficient methods of collecting geographic information that has certain advantages compared to terrestrial observations (terrestrial surveying). The most important of such features are addressed here.
Mahdi Modiri
Volume 9, Issue 34 , August 2000, , Pages 2-5
Abstract
It is now more than thirty years since the important parts of photogrammetry have been automated. One of the primary applications of photogrammetric automation is to digitize the data of the device's measurement system using the numerical stability system. In general, the coordinates of automatic drawings ...
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It is now more than thirty years since the important parts of photogrammetry have been automated. One of the primary applications of photogrammetric automation is to digitize the data of the device's measurement system using the numerical stability system. In general, the coordinates of automatic drawings are used by converting devices (the photo-mapping converting system). This device receives the order through a computer, which receives the commands and coordinates of the model’s points from the machine and transmits them to this device. The set of encoders, the servomotor system, and the computer with a stereocomparator make up the analytical photogrammetric system.
Mahdi Modiri
Volume 9, Issue 33 , May 2000, , Pages 2-4
Abstract
Positioning based on satellite systems began in early 1961. GPS was evolved over time with the aim of supporting military navigation and fulfilling the need for quick and accurate positioning in the shortest possible time. Vast military needs led to continuous follow-up of spatial systems’ situation. ...
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Positioning based on satellite systems began in early 1961. GPS was evolved over time with the aim of supporting military navigation and fulfilling the need for quick and accurate positioning in the shortest possible time. Vast military needs led to continuous follow-up of spatial systems’ situation. One of the early and successful systems was the Transit Satellite. The Doppler system is formed by six satellites. These satellites revolve on polar paths around the earth at an elevation of about 1000 km from its surface. The Loran, Decca and Sat-Nav systems are among the positioning systems in operation before GPS which provided relatively high efficiency in air and marine navigation and control. GPS is a complete system. Its initial plan was designed as two projects in the U.S. Air and Marine Forces in 1960, and its major activities began in 1973 by the Ministry of Defense, which was met with rapid success. Since 1983, this technology was introduced into non-military applications such as geodetic networks, aerial navigation, photogrammetry with least ground control points, cadaster, changes in shape of the earth’s crust, marine navigation, direction of urban transportation systems, control of robots, etc.GPS is formed by three parts: Space part (satellite); system control stations; ground receiver (users).
Mahdi Modiri
Volume 8, Issue 32 , February 1999, , Pages 2-3
Abstract
The basis of decision-making and selection of Geographic Information Systems (GIS) is the quality of geographic information. Many executive centers of geographic information systems and their users usually seek application and utilization of more powerful computers with various abilities such as high ...
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The basis of decision-making and selection of Geographic Information Systems (GIS) is the quality of geographic information. Many executive centers of geographic information systems and their users usually seek application and utilization of more powerful computers with various abilities such as high volume of memory, power of processing and graphic display (size, color and form of display) as well as a variety of programs capable of analysis and modeling, and concern less about the quality of information. It is so while today many of GIS managers’ expectations have not yet been fulfilled and many promises have failed despite vast investments in provision of hardware systems and collection, provision and storage of geographic data.Quality of information is one of the most important issues that has received less attention. Quality of information is in direct connection with precision, clarity, scientific bases of combination of information, analysis and modeling.In general, effective and determining factors can be categorized into four branches: geographic information database; structure of information; storage, search for data, distribution and propagation of information; and cartographic process of information and its necessary considerations.
Mahdi Modiri
Volume 8, Issue 31 , November 2009, , Pages 2-5
Abstract
Considering the fast growth of population and the following urban development and expansion, the International Federation of Surveyors (FIG), during its permanent commission attended by a delegates of land management experts, has published a declaration concerning the importance of land management and ...
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Considering the fast growth of population and the following urban development and expansion, the International Federation of Surveyors (FIG), during its permanent commission attended by a delegates of land management experts, has published a declaration concerning the importance of land management and the role of surveying engineers in development of human habitation.The declaration has been prepared by collaboration of the UN’s Habitat, and can achieve its goals only if its recommendations are implemented; so it is asked from all countries to stay committed to fulfilment of the declaration’s requirements, and the international society is to use all its power to realize its goals.In the FIG congress in Helsinki, the head of the UN’s Habitat has declared:“Land is the starting point of all human habitation, and surveying engineers stand at the first stage of this process”.This statement shows the cosmopolitan responsibility of the surveyor. This paper describes the issues related to the content of this declaration.
Mahdi Modiri
Volume 8, Issue 30 , August 1999, , Pages 2-4
Abstract
Aerial photography is one of the best methods of collecting geographic information which, considering its various applications, has been one of the most suitable tools for the valuable science of surveying over the past century. After the end of the World War II, aerial photography experienced remarkable ...
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Aerial photography is one of the best methods of collecting geographic information which, considering its various applications, has been one of the most suitable tools for the valuable science of surveying over the past century. After the end of the World War II, aerial photography experienced remarkable progress, and preparation of aerial photos of areas in a short period of time became possible. In 1918, in a period of four days of war, 56,000 aerial photos were prepared. In the period between two World Wars, application of aerial photos was significantly slowed down. In armed forces, interpretation of aerial photos was in direct connection with precision of photography as well as exact geometric conditions and their up-to-date information. Later, valuable progress was made in commercial and scientific branches of aerial photo preparation, and military surveying organizations practiced aerial photography, interpretation of aerial photos and conversion of photos into maps. Utilization of aerial photos for accurate measurements in photogrammetry become common. The ground-based technique of topographic map preparation was reduced in necessity and provision of maps from areas difficult to pass became possible. Germany, familiar with the importance of aerial photos and their interpretation during the Second World War, based its plans on utilization of coverage photos of forest regions. Interpretation of aerial photos was applied in estimation of the depth of waters. After the Second World War, the experiences obtained during the war regarding interpretation of photos became a basis for varied applications of it in reconstruction and peaceful developmental activities, including preparation of topographic coverage maps and developmental and cadaster large-scale maps.
Mahdi Modiri
Volume 8, Issue 29 , May 1999, , Pages 2-5
Abstract
Currently, Geographic Information Systems (GIS) are useful software packages in which many tools and models are as strange for users as a factory of robot assembly for a simple worker (Barrow, 1991). Unfamiliar terms limit GIS application and make users unaware of the fact that a set of data is the product ...
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Currently, Geographic Information Systems (GIS) are useful software packages in which many tools and models are as strange for users as a factory of robot assembly for a simple worker (Barrow, 1991). Unfamiliar terms limit GIS application and make users unaware of the fact that a set of data is the product of a long-term process that significantly limits data usability. There are methods for description of spatial data which are informally common.
Today in many countries the process of preparation of basic (benchmark) coverage maps has replaced new automatic methods. But in many mapping machines the preparation of maps is still in the form of production and storage of copies of maps on various scales. There are different reasons for this fact, including:
Tools necessary for production and implementation of different stages of generalization of geographic data are not available;
Suitable system for multiplication and spread of new information resulted from a series of data is not possible to provide;
The process of correction of vast data needs great amount of time. (Muller et al., 1995)
Mahdi Modiri
Volume 7, Issue 28 , February 1998, , Pages 2-5
Abstract
Among various complex modeling techniques that can be used in research, there is great difference between techniques considering “what is there?” or “what can be there?” and those dealing with “what should be there?”. This difference can be expressed through descriptive ...
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Among various complex modeling techniques that can be used in research, there is great difference between techniques considering “what is there?” or “what can be there?” and those dealing with “what should be there?”. This difference can be expressed through descriptive and prescriptive models.
Descriptive modeling techniques aim at clarification and description, and it is possible to make distinctions between techniques which analyze cartographic data and those which combine such data. Techniques aiming at analyzing cartographic data decompose data into conceptually clearer levels, while techniques combining data attempt to combine them for utilization in a particular texture.
Analytical techniques of cartographic data usually deal with characteristics concerning position or form, and in the hill model (example mentioned in the main text) both can be observed. In Travel Time Layer in fig.6, the positional characteristic of each point relative to a hill is determined in terms of minutes.
Mahdi Modiri
Volume 7, Issue 27 , November 1998, , Pages 2-11
Abstract
Cartographic modeling is the general and customary method of geographical data analysis. What is used in cartographic modeling leads finally to certain algebraic relationships in which each one of effective factors in thematic combination of maps acts as a variable, and it is possible to change these ...
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Cartographic modeling is the general and customary method of geographical data analysis. What is used in cartographic modeling leads finally to certain algebraic relationships in which each one of effective factors in thematic combination of maps acts as a variable, and it is possible to change these variables using functions and cartographic combination in a flexible manner. In this paper, the rules, ability and major techniques of this methodology are briefly examined.
Mahdi Modiri
Volume 7, Issue 26 , August 1998, , Pages 2-6
Abstract
Most of satellite images are received in digital form and the logical way of dealing with them is digital processing. Human interprets images very well. However, our eyes have limitations in observing black-and-white pictures in a range of electromagnetic waves’ spectra through looking at colored ...
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Most of satellite images are received in digital form and the logical way of dealing with them is digital processing. Human interprets images very well. However, our eyes have limitations in observing black-and-white pictures in a range of electromagnetic waves’ spectra through looking at colored images and a combination of different bands. It is possible that at one time they look at a particular part of three bands in a colored combination, so other bands are not used. eye is not able to fully distinguish different infrared reflections of a picture from that of another picture, while near infrared, in comparison with red waves reflection, provides useful information about various features and phenomena, especially plants. Techniques we deal with are implemented through digital analysis of images. it does not mean that visual interpretation of satellite images is not useful, but it can be highly valuable, and information can be extracted through common visual interpretation methods such as color, tone, size, shape, figure and texture of image.
Mahdi Modiri
Volume 7, Issue 25 , May 1998, , Pages 2-8
Abstract
In automatic cartography, information output systems constitute a very important part. Information technology and output methods always go through their evolution according to mapping goals, and the role of information output is such that contrary to classic cartography, it is not the end of mapping ...
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In automatic cartography, information output systems constitute a very important part. Information technology and output methods always go through their evolution according to mapping goals, and the role of information output is such that contrary to classic cartography, it is not the end of mapping process, but a beginning to a variety of applications of digital maps and an emphasis on the scientific-engineering role of surveying and cartography engineers at stages of map utilization (design, implementation, supervision and control of projects).
Mahdi Modiri
Volume 6, Issue 24 , February 1997, , Pages 2-6
Abstract
Computer can be programmed in order to draw maps at different graphic levels with the help of various output systems including printers, plotters and display systems. These automatic graphic machines share one attitude: they carry out whole or part of drawing with reliable speed and accuracy several ...
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Computer can be programmed in order to draw maps at different graphic levels with the help of various output systems including printers, plotters and display systems. These automatic graphic machines share one attitude: they carry out whole or part of drawing with reliable speed and accuracy several times greater than human’s hand. On the whole, basic information of these maps, implemented by manual or automatic methods, must be fed into computers.
Mahdi Modiri
Volume 6, Issue 23 , November 1997, , Pages 2-5
Abstract
In order to process cartographic information, it is necessary to determine the topological structure of data so that database becomes intelligent and ready for analysis and transfer. After collection of various data, a database with consistent topological and geometric structure should be created. This ...
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In order to process cartographic information, it is necessary to determine the topological structure of data so that database becomes intelligent and ready for analysis and transfer. After collection of various data, a database with consistent topological and geometric structure should be created. This task begins with conversion of all types of data and their matching on a single scale and selection of a single image or network coordinate system. But in raster computer maps and GIS there is need for something else. All pixels must be of same shape and size.
Mahdi Modiri
Volume 6, Issue 22 , August 1997, , Pages 2-3
Abstract
Statistical analysis is an important tool for environmental planning, control and assessment. Most geographic information systems determine basic descriptive statistical indexes such as mode, mean, average, minimum/maximum and quantitative data of standard deviation, and describe characteristics that ...
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Statistical analysis is an important tool for environmental planning, control and assessment. Most geographic information systems determine basic descriptive statistical indexes such as mode, mean, average, minimum/maximum and quantitative data of standard deviation, and describe characteristics that occur in a certain area, including determination of the average elevation in the area within a radius of five kilometers around a point or provision of diagrams of frequency which show the distribution of values from least to most within an area. Simple statistical comparison of two or more data layers such as cross tabulation can usually be carried out within the framework of database management system created in GIS, and complex methods such as multi-regression and analysis of variance can usually be implemented by transferring data files from GIS to a general or special statistical analysis software package which has a range of progressive analysis methods, and then transfer the results back to GIS.
GIS modeling is related to application of more complex mathematical methods for prediction of numerical values of environmental phenomena such as solar radiation or soil degradation at a particular point in the studied area. Models are based on simple linear equations which can be considered as a series of mathematical operations within the framework of GIS. Most of progressive models, including those based on solution of differential equations with several repetitions to reach the desirable solution, need a connection between GIS data and a suitable modeling program. The results are usually received in the form of new data layers that can be used in future analyses. These types of file transfer are necessary in any kind of analysis, because it is not reasonable to expect a geographic information system to have all modeling methods.
Mahdi Modiri
Volume 6, Issue 21 , May 1997, , Pages 2-3
Abstract
Among advanced inventions and techniques, preparation and production of maps has undergone wonderful changes and transformations more than any other field. Computer progress and development of maps has reached a level that currently microcomputer programs have made users able to design and make a variety ...
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Among advanced inventions and techniques, preparation and production of maps has undergone wonderful changes and transformations more than any other field. Computer progress and development of maps has reached a level that currently microcomputer programs have made users able to design and make a variety of maps through interconnections.
Current programs of mapping are in alignment with hardware systems of general cartographic design and drawing; they produce different files of map and move the laser imaging devices to deliver positive and negative lithographic films for making gravure. In this regard, the computer technology has transformed reading and analysis of maps. Electronic display of virtual maps (without any “real” activity) allows users to utilize powerful systems of cartographic display such as electronic atlases for quick exploration and comparison of statistical data or preparation of value maps.
Mahdi Modiri
Volume 5, Issue 20 , February 1996, , Pages 2-3
Abstract
In the map and image printing process, several factors contribute to the reduction of accuracy and esthetic appeal. In fine print works, half-tone points have a diameter of about 0.2 millimeters; these points, like many small objects, undergo deformation and gain complexity on the big-world, human and ...
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In the map and image printing process, several factors contribute to the reduction of accuracy and esthetic appeal. In fine print works, half-tone points have a diameter of about 0.2 millimeters; these points, like many small objects, undergo deformation and gain complexity on the big-world, human and physical scales. When pixels and half-tone points are transmitted from address network to print page, mathematical shapes are affected by physical machines. Lithography, printing process and mechanical complications are also added. These disturbances affect the final image, and the degree of this effect depends on the nature of the half-tone structure, the nature of the image and the physical process.
In order to avoid any increase of half-tone disadvantages, awareness of the factors affecting the image is necessary. Here the various sections of the common method are reviewed briefly.
Mahdi Modiri
Volume 5, Issue 19 , November 1996, , Pages 2-7
Abstract
In reproduction and printing of an image, it is not possible to create an image similar to the original one, and there is no need for it. In order to provide an acceptable image, what is necessary is a tonal display. In this operation, the eyes and brain assist to compensate for the difference in light ...
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In reproduction and printing of an image, it is not possible to create an image similar to the original one, and there is no need for it. In order to provide an acceptable image, what is necessary is a tonal display. In this operation, the eyes and brain assist to compensate for the difference in light between the tone and the colored backgrounds.
Before we obtain an acceptable tonal picture, we need to examine the image reproduction system and its features. There are two general categories of image reproduction systems: Systems that have the ability to provide acceptable tones and systems that cannot do this.
Mahdi Modiri
Volume 5, Issue 18 , August 1996, , Pages 2-3
Abstract
One of the important points in displaying the ground features on map is tone and tonal relationship. What sets up the provider-user connection in maps and conveys the message is a set of signs, symbols and colors.
The signs and symbols of each map can be divided into real and virtual symbols, each ...
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One of the important points in displaying the ground features on map is tone and tonal relationship. What sets up the provider-user connection in maps and conveys the message is a set of signs, symbols and colors.
The signs and symbols of each map can be divided into real and virtual symbols, each of which contains point (spatial), linear and surface marks.
• Real point signs include cases such as geodetic and levelling points, lighthouse, springs, mosques, stations, etc.; linear such as road networks, railways, watercourses, rivers and power lines; surface signs like forests , ranges, farms, salt pans (Kavir), parks and many more; • Virtual signs are also in the form of points, lines, and surfaces; virtual point signs such as magnetic north; linear sings such as international political, provincial, county, district and rural boundaries, aerial paths of aircrafts and ships’ sailing courses; surface signs including protected areas, climatic divisions, etc.
Mahdi Modiri
Volume 5, Issue 17 , May 1996, , Pages 2-5
Abstract
GIS, like other information systems, consists of sub systems. • Data entry sub-system; • storage and data-recovery Subsystem; • processing and data analysis Subsystem; • Information outlet Subsystem.
A system can be called a GIS whose software system includes all four of the above ...
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GIS, like other information systems, consists of sub systems. • Data entry sub-system; • storage and data-recovery Subsystem; • processing and data analysis Subsystem; • Information outlet Subsystem.
A system can be called a GIS whose software system includes all four of the above functions. Consequently, most digital mapping systems, remote sensing systems, and thematic mapping systems are not GIS.
Today, database management and analysis are important functions, but in the future, modern functionalities such as the use of artificial intelligence or visualization might come about, which will be among the most prominent features of GIS, and there is no reason why GIS should be limited only to the technology.
Mahdi Modiri
Volume 4, Issue 16 , February 1995, , Pages 2-5
Abstract
Attitude toward map as a medium of communication and cartography language has evolved over the past four decades.
Cartographers, while devoting their efforts to different surveying techniques and seeking to adapt to the advancements in technology, must examine the performance and design of the maps. ...
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Attitude toward map as a medium of communication and cartography language has evolved over the past four decades.
Cartographers, while devoting their efforts to different surveying techniques and seeking to adapt to the advancements in technology, must examine the performance and design of the maps. In this way, cartography becomes the knowledge of geographic information communication. The research on messaging and cartographic communication is significant in two historical periods. Cartography in the early fifties of the twentieth century found the methodology of psychophysics in the seventh decade of cartography research in the direction of cognitive psychology of development and evolution, and the question of how maps are processed and remembered in human’s mind was formed. This emphasis on cognitive problems in cartography did not extend as much as psychophysics, and in fact cognitive and perceptual powers were not uniformly available for cartography.
Mahdi Modiri
Volume 4, Issue 15 , November 1995, , Pages 2-6
Abstract
The Cartographic Information System (GIS) produces a map, and the output can be graphic, printed or maps on the computer screen. Maps are generally different in appearance and dimensions. It is sometimes difficult to say that a product or output is an image or a map on a computer screen, which has a ...
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The Cartographic Information System (GIS) produces a map, and the output can be graphic, printed or maps on the computer screen. Maps are generally different in appearance and dimensions. It is sometimes difficult to say that a product or output is an image or a map on a computer screen, which has a different name from paper maps. In the history of automatic cartography, the term "temporary map" and "permanent map" have been used. According to Riffe, a temporary map is the one that appears on the screen, or maps on the screen that have a conventional application. Temporary maps can be referred to as “intelligent maps”, which, in the strict sense of the word, are actually not available today. Riffe defines the term “non-map” in this way; data is obtained from sensors that are used in navigation and traffic control. He states that future maps are all temporary maps and non-maps. Morrison uses the title "Temporal Map" as a synonym for maps on the computer screen, and then uses the title "Printed Map" in contrast with it. The term “instant map” has also been used for the computer screen map.
Mahdi Modiri
Volume 4, Issue 14 , August 1995, , Pages 2-5
Abstract
The computer-based system's structure is mainly hierarchical and GIS is a hierarchical structure that is made up of several sub-systems at different levels, and each sub-system has a certain function. The required set of functions is different according to the type of GIS. Examples of a sub-system include ...
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The computer-based system's structure is mainly hierarchical and GIS is a hierarchical structure that is made up of several sub-systems at different levels, and each sub-system has a certain function. The required set of functions is different according to the type of GIS. Examples of a sub-system include the function of input data and devices, data analysis function, and data management function.
The display and spatial visualization of geographic data can be considered as a GIS sub-system (it should be noted that in cases such as maps preparation, displaying data is the fundamental function of the system.).
We know that cartography is the art, science and technology of mapping (ICA 1973), and in order to achieve alignment with the scientific and technical advancements of the day, the International Cartographic Association's Working Group has recommended the following definition.
Mahdi Modiri
Volume 4, Issue 13 , May 1995, , Pages 2-5
Abstract
The cost of collecting basic information accounts for about seventy five percent of the total cost of geographic information systems. Satellite images, while significantly reducing the cost of providing geographic information, improve the orderly revision and update of information, and provide satellite ...
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The cost of collecting basic information accounts for about seventy five percent of the total cost of geographic information systems. Satellite images, while significantly reducing the cost of providing geographic information, improve the orderly revision and update of information, and provide satellite imagery with technically advantages such as:
• A comprehensive and consistent view of each area of land; • Ability to regularly and continuously revise and update geographic information; • direct transfer of digital satellite imagery to the GIS; • access to archives of satellite images easily.
Currently, a large part of the Earth's surface measurements are obtained from satellites. This will revise and expand our understanding of different conditions of the earth. Remote-exploration satellites provide an opportunity for continuous multi-time measurements from a wide area during a particular period of time. For this purpose, satellite data should be in a suitable format and in a manner consistent with other ground information in the GIS.
Mahdi Modiri
Volume 3, Issue 12 , February 1994, , Pages 2-5
Abstract
So far, there have been a lot of definitions of GIS, all of which trying to say what GIS is. However, today's modern systems of GIS share two forms of vector and network data. Users' demand for vector/network data of image layers including digital orthophoto has increased dramatically. There have been ...
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So far, there have been a lot of definitions of GIS, all of which trying to say what GIS is. However, today's modern systems of GIS share two forms of vector and network data. Users' demand for vector/network data of image layers including digital orthophoto has increased dramatically. There have been vast discussions In connection with the application of GIS, but what is to be more emphasized is the practical context and objective realization of the use of geographic information systems. In this issue, examples of defensive use, disaster management, astronomical research, and optimal use of natural talents and facilities are addressed, hoping that in the future successful cases of GIS activities will be presented.
Mahdi Modiri
Volume 3, Issue 11 , November 1994, , Pages 2-3
Abstract
Any information system can be simply a manual system or a complex computer one.
In a general view, information systems that are used in different ways seem to be diverse. But in fact all have a common goal, which is to provide a conventional method for collecting, storing, processing and providing ...
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Any information system can be simply a manual system or a complex computer one.
In a general view, information systems that are used in different ways seem to be diverse. But in fact all have a common goal, which is to provide a conventional method for collecting, storing, processing and providing information. In other words, it can be said that it covers a limited amount of specialized information available for the user, or a wide range of information on various topics in meeting the needs of a wide range of users; for example:
We can consider a library as a system of manual reception of information. Library catalogue cards comprise a database and the library staff, library users, administrative regulations, equipment (cards), and data (books) form the information system. In an automatic information system, people and data are like a manual system, but equipment and regulation change. In an automated system, it is necessary for storing data to use appropriate software and hardware, and where there is a huge amount of information, the existence of automated systems is essential.
Mahdi Modiri
Volume 3, Issue 10 , August 1994, , Pages 2-4
Abstract
The base and main essence of GIS in today's world is to provide reliable tools of decision-making based on geographic information. Given the wide-ranging applications of GIS, the new features considered for it, the accessibility, true dynamism, efficiency and practical advantages of GIS, it is expected ...
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The base and main essence of GIS in today's world is to provide reliable tools of decision-making based on geographic information. Given the wide-ranging applications of GIS, the new features considered for it, the accessibility, true dynamism, efficiency and practical advantages of GIS, it is expected that the GIS range of users find broader aspects. The base and essence of GIS in today's world is to provide reliable decision-making tools based on geographic information, and the presence of surveying engineers in the GIS environment requires careful planning, which is the basis for decisions and a guidance for future work. In an overview based on the diversity of working environment, GIS can be categorized as such: Collection of information; Combination of information; analysis of information; Presentation of information.
Mahdi Modiri
Volume 3, Issue 9 , January 2018, , Pages 2-4
Abstract
For easy understanding and quick access, all types of geographic information are displayed on maps, because displaying information graphically is, in many cases, more indicative than a number of books on the same matter. Any modification or revision of information in maps requires development of a new ...
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For easy understanding and quick access, all types of geographic information are displayed on maps, because displaying information graphically is, in many cases, more indicative than a number of books on the same matter. Any modification or revision of information in maps requires development of a new map with a process similar to that of the first map. In fact, the information on map is not always exploited and sometimes finds only quantitative value as archives.
Mahdi Modiri
Volume 2, Issue 8 , February 1993, , Pages 2-4
Abstract
Remote sensing is a science that provides valuable information about land objects and phenomena through distant measurement and without physical contact. As mentioned in the last issue, information can be obtained by measuring and recording changes in electromagnetic fields, gravity and sound waves. ...
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Remote sensing is a science that provides valuable information about land objects and phenomena through distant measurement and without physical contact. As mentioned in the last issue, information can be obtained by measuring and recording changes in electromagnetic fields, gravity and sound waves. Remote sensing is the information that can be exploited by measuring the reflection of electromagnetic waves of the atmosphere and the earth's surface and received by sensors that are installed on the satellites, and after analysis, the necessary information is extracted. Remote sensors are divided into two main active and passive groups based on source of energy and light. Active sensors such as radar have artificial energy source, and inactive sensors have a natural energy source (the sun) and are similar to cameras and scanners. They act through reflecting information in photographic and digital forms.
Mahdi Modiri
Volume 2, Issue 7 , August 1993, , Pages 2-6
Abstract
The daily scientific development and advancements increase the scope and application of surveying in different sciences day by day. The modern technology has always provided new applications for this science, so that even the medical sciences utilize a branch of it. Today there is rarely any case within ...
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The daily scientific development and advancements increase the scope and application of surveying in different sciences day by day. The modern technology has always provided new applications for this science, so that even the medical sciences utilize a branch of it. Today there is rarely any case within applied sciences and developmental activities that can be carried out without any need to understand the environment, geographical position, and natural conditions and potential. More emphasis on rational planning makes the importance of accuracy of information about the quantitative and qualitative situation of the environment multiplied, for example, in urbanization and regional planning. The number of services of surveying and the scope of its contribution to scientific and technological advances is increasing.
Mahdi Modiri
Volume 2, Issue 6 , February 1992, , Pages 2-5
Abstract
One of the major steps in surveying is the activity called the "classification operation". An operation that, while clarifying aerial photographs, collects the information of names. Classification operations have specific technical rules and regulations that the Geographic Organization has described ...
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One of the major steps in surveying is the activity called the "classification operation". An operation that, while clarifying aerial photographs, collects the information of names. Classification operations have specific technical rules and regulations that the Geographic Organization has described in the publications of the same name, a brief account of which is presented here.
The classification of aerial photos includes the actions taken on the draft of the map before cartography operation, including some of the activities listed below:
- Identification and classification of the features of natural and artificial effects and displaying them by conventional signs; - Providing information and names.
Mahdi Modiri
Volume 2, Issue 5 , August 1992, , Pages 2-5
Abstract
Since thousands of years ago, human’s activities on the earth have been accompanied by thoughts concerning where to be and where to go, how to move and in which direction. Living in nature and thinking about land and its various forms drove people to thought; human beings had to understand their ...
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Since thousands of years ago, human’s activities on the earth have been accompanied by thoughts concerning where to be and where to go, how to move and in which direction. Living in nature and thinking about land and its various forms drove people to thought; human beings had to understand their surroundings in order to be able to live. In distant past, human knowledge of the environment was limited to the extent of human settlements known in those days, and to the extent that the physical strength of people and natural barriers allowed. Human being used his brain and hands and drew different forms of nature in order to understand, and help others understand, the nature, and to exploit findings and experiences of other people. Utilization of drawing in order to identify places became so persistent an activity in human life that it is now considered a natural practice. Since the drawings needed to be correspondent to reality, gradually careful drawing and measurement entered into consideration, and this step should be considered as the beginning of surveying and science of cartography (mapping technology).
Mahdi Modiri
Volume 1, Issue 4 , May 1992, , Pages 2-3
Abstract
At the same time as practical and technological developments and mutual impact in raising the quality and scientific potential of surveying services, manufacturers of technical devices and equipment also struggle day by day to present new achievements. Over the past three years, with the exit of analogue ...
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At the same time as practical and technological developments and mutual impact in raising the quality and scientific potential of surveying services, manufacturers of technical devices and equipment also struggle day by day to present new achievements. Over the past three years, with the exit of analogue photogrammetric devices from the market and their replacement with analytical devices, there has been a remarkable transformation in the field of surveying and utilization of computer in that field, and extraordinary progress can be witnessed every day in the field of small and large analytical devices that use microcomputers. What’s more, a series of modern photogrammetric devices are introduced into market by manufacturers that have often had no connection with photogrammetry and mapping in the past. There are many innovative ideas available on these small but powerful devices many of which have applied aspects in the fields of photogrammetry, preparation of thematic maps and revision of previously made maps. Another valuable innovation and initiative which should be mentioned is conversion systems for the purpose of an appropriate transformation of analogous photogrammetric devices into analytical ones.
Mahdi Modiri
Volume 1, Issue 2 , February 1990, , Pages 2-3
Abstract
The rapid access to geographic information (recognition of the face of the earth, geographic location and conditions, atmospheric phenomena, human communities, etc.) is an attempt that is today being made by the world’s “practical-technical” centers.
Geosciences and surveying are ...
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The rapid access to geographic information (recognition of the face of the earth, geographic location and conditions, atmospheric phenomena, human communities, etc.) is an attempt that is today being made by the world’s “practical-technical” centers.
Geosciences and surveying are some of the few practical fields that place all human beings in their territory because human beings are all interested in understanding their surroundings and looking for the proper utilization of it. This recognition is not possible except through geographic surveys and maps or direct observation and experience, which will be time-consuming and costly. Military goals, Sailing, Aviation, Geological studies, control of rivers and flowing waters, construction of dams and water canals, land restoration, protection of natural forests and pastures, port and pier making, Construction and development of villages, reconstruction of cities damaged by war or natural and unexpected disasters, the establishment of new towns and cities, the determination of land borders, the internal and water borders, the dry land borders, the creation of electricity and gas deliverance networks and hundreds of other vital issues all in the general sense require the existence of a map of the area as the basis for studying and planning. Geographic sciences with all their practical branches are intended to express the interactions among natural phenomena, technology, human beings and how to properly utilize the facilities, and have been closely linked with cartography from the very beginning and have already made human access to geographic information possible.
Mahdi Modiri
Volume 1, Issue 1 , May 1990, , Pages 2-3
Abstract
Surveying sciences, mathematics, astronomy and geography have had deep connections with each other from the outset. At any given time, these scientists have been able to play a key role in the increasingly better introducing the picture of the earth, determining the location of the points and introduction ...
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Surveying sciences, mathematics, astronomy and geography have had deep connections with each other from the outset. At any given time, these scientists have been able to play a key role in the increasingly better introducing the picture of the earth, determining the location of the points and introduction of geographical conditions by exploiting the technology and technical possibilities and by combining iron with art. The roots of these sciences go back to very distant past (several centuries BC, simultaneously with the emergence of the thought of creating maps), but the advent of Islam, which brought about dramatic changes in the social dimensions of humanity, contributed greatly to the dissemination of human sciences and knowledge. Islam has begun its first message with Eghra’ (read aloud), in other words, the first chapter of the Holy Qur'an is based on the pursuit of knowledge.
Yasser Ebrahimian GhaJary; Ali Asghar Alesheikh; Mahdi Modiri; Reza Hosnavi; Morteza Abbasi
Abstract
Throughout the history, cities have neverbeen safe due to the damages caused by human and natural disasters. So that inthe past, the cities were the war’s last target, but now with the development of technology, those hindrances have turned into the first wartargets. In fact, what poses war andair ...
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Throughout the history, cities have neverbeen safe due to the damages caused by human and natural disasters. So that inthe past, the cities were the war’s last target, but now with the development of technology, those hindrances have turned into the first wartargets. In fact, what poses war andair raids as a threat, is just the problem ofencountering it and being. One major way to prepare facing such threats, is the knowledge about the degree of its vulnerability whenthey occur. So, it depends on taking up some methodsto diminish the vulnerability instability. Whatthe researchers were looking for, was the modelling the vulnerabilityof the city buildings (one of the most important urbancomponent) in one part of theTehran (region 6 of Tehran municipality). Since vulnerability is made upof various criteria, so the proposed model in this researchis a kind of multi-criteria model (multi attribute decisionmodel), and according to the spatial essence of the criteria, this model has been carried out in GIS (MCDM-GISmodel). Delphi method has been used to survey major vulnerabilityfactors with the help of urban passive defense, structure, andarchitecture experts. The modelling of the 9 criteria has resulted throughAnalytic Hierarchical Process (AHP), and it shows that about 38percent of building has low vulnerability, about 60 percent has mediumvulnerability and 2 percent has high vulnerability (over 60 percent of buildingshas plus-average vulnerability) which shows the necessity for taking actions in order todecrease vulnerability through passive defense.
Nagmeh Neisany Samany; Mahmoud Reza Delavar; Mohammad Reza Malek
Abstract
Navigation is one of the most important daily activities of individuals in an urban environment. The spatial information systems of the user guidance are the most common services which guide people to navigate the various routes with different goals.The main challenge of such systems is providing context-aware ...
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Navigation is one of the most important daily activities of individuals in an urban environment. The spatial information systems of the user guidance are the most common services which guide people to navigate the various routes with different goals.The main challenge of such systems is providing context-aware navigation information. The location, time,and the identifier of the individual person are among the primary contexts and the other related contexts are modeled based on these contexts. The present paper attempts to model the spatial-temporal communication of the moving user based on the identifier of the individuals. So that it covers all spatial communications (topologic, metric and directional) in time dimension andtakes the characteristics of the user and the related contexts into consideration. In this regard, the proposed model utilizedthe advantages of Allen’s Multi-Interval Algebra (MIA) and dynamic Voronoi-based Continuous Range Query (VCRQ), and introduceda new method by following the large calculus principles and the existing customization methods. The designed model (MIA25) was implemented in a software applicable in mobile systems. The evaluation of the implemented model in the tourist’s navigation scenariointhe regions 3, 6, and 11 of Tehran municipality was carried out based on 3 parameters of accuracy, runtimeand users’ satisfaction. These three regions were selected as the case study area. In order to test the accuracy of the model, the designed software was iterated 100 times in three different routes in the study area by three different tourists at three time intervals with two different average speed. Then, the recognition of each one of the textures existing on the way, was examined by the one-way binomial approximationwith 95% of confidence level over 100 iterations. Also, two indices of correctness and recall were used to evaluate the recognition of the textures through the entire route. The results of implementation and evaluation of the model based on three parameters of accuracy, runtime and users’ satisfaction demonstrate the efficiency of the proposed model in an urban context-aware navigation system.
Behnam Bigdeli; Mohammad Javad Valadan zoj; Yaser Maghsoudi Mehrani
Abstract
Collecting information on the areas under cultivation of wheat and the amount of its products provides the successful and sustainable management in the economic policy-makingfor this strategic product. Introduction of high spectral and special resolution satellite data has enabled the production of such ...
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Collecting information on the areas under cultivation of wheat and the amount of its products provides the successful and sustainable management in the economic policy-makingfor this strategic product. Introduction of high spectral and special resolution satellite data has enabled the production of such information in a timely and accurate manner. Investigating the spectral reflection of plants using field spectrometry and forming a spectral library increases the possibility of differentiating various wheat cultivars and preparing their distribution map. For this purpose, the spectral behavior curves for 6 wheat cultivars named Bahar, Chamran, Pishtaz, Shiraz, Shiroodi and Yavaros, were measured at three stages of growth at the ‘Research Institute of Seed and plant improvement " of Karaj in Iran. Observations were obtained by the ASD FieldSpec®3 Field Spectrometerin the range of 350-2500 nm wavelength under natural light and natural conditions. In the pre-processing stage, three noisy ranges affected by water vapor were detected and eliminated to enhance the gathered data quality. Then,in order to qualitatively collect the data, wrong observations were excluded using statistical methods. This research was designed and implemented in two main steps. In the first step, the spectral response function of the OLI sensor installed on the Landsat 8 satellite was applied to the library's spectra. Then, using the spectral similarity criteria and the twenty seven important vegetation indices sensitive to chlorophyll concentration, photosynthesis intensity, nitrogen and water content in the crown of the plant, etc., the extreme final resolution of wheat cultivars under study, was estimated.In the second step, the classification of the identified farms was carried out by conducting a field survey of the studied area and obtaining satellite images of the target sensor using spectral library spectra. The results showed a significant separabilityof Yavarus wheat variety from other cultivars, both in field spectra and satellite images.
Monireh Shamshiri; Mahdi Akhondzadeh Hanzaei
Abstract
Discussion about earthquake to reduce its casualties and damages is very important, especially in a seismic area like Iran where the occurrence of this natural phenomenon is seen annually. Anomaly detection prior to earthquake plays an important role in earthquake prediction. Ionosphere changes which ...
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Discussion about earthquake to reduce its casualties and damages is very important, especially in a seismic area like Iran where the occurrence of this natural phenomenon is seen annually. Anomaly detection prior to earthquake plays an important role in earthquake prediction. Ionosphere changes which are recognizable by remote measurements (such as using Global Positioning System) are known as earthquake ionospheric precursors. In this study, two data sets from the ionospheric Total Electron Content (TEC) derived from the GPS data processing by Bernese software were used for two studies, Ahar earthquake, East Azerbaijan (2012/08/11) and Kaki earthquake,Bushehr (2013/4/9), and the results were compared with data obtained from the global stations. Because of the nonlinear behavior of TEC changes, in order to predict and detect its changes, integration of neural network (using multilayer Perceptron (MLP)) with particle swarm optimization algorithm (PSO) was used. Particle Swarm Optimization algorithm with a performance based on the population can be effective in improving estimatedweight by artificial neural network. By analyzing the causes of ionospheric anomalies including the geomagnetic fields and solar activities and their removal from the processes, the results indicate that some of this anomalies caused by the earthquake and using intelligent algorithms were able to have appropriate efficiency for the prediction of nonlinear time series. The output resulted from the integration of artificial neural network and PSO shows that both positive and negative anomalies occur. The anomalies before earthquakes often occur close to the epicenter of the earthquake and are visible 3 days before the Ahar earthquake and 2 to 6 days before the Kaki earthquake are.
Hamid Bagheri; Mohammad Reza Malek; Ali Esmaeilie; Mahdieh Ghodsinejad
Abstract
In recent decades, the limitation of urban water resourcesand the wear and tear of transmission lines, the short life span of water network elements, the increasing fracture of pipes and the high losses of networks have led to increased economic and social costs in the utilization of distribution network ...
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In recent decades, the limitation of urban water resourcesand the wear and tear of transmission lines, the short life span of water network elements, the increasing fracture of pipes and the high losses of networks have led to increased economic and social costs in the utilization of distribution network infrastructures. Lack of information, oldness of network data and the absence of spatial information system for incidents is one of the major problems facingmanagement of water transmission networks. Although the provision of such data is supervised by government agencies and is subject to certain standards, the problem of shortage, defect and delay is still evident. One of the solutions proposed to solve this problem is the use of citizen participation in the provision of spatial data. Using the Volunteered Geographic Information environments and the Information ofnative people can be a quicker and less costly method to update the maps. In the context of the present paper, Volunteered Geographic Information environment was used to accelerate the process of servicing in urban water network in cases of problems such as water pipes leakage, pipes rupture, illegal excavations, etc. After modeling and designing the proposed system, it was implemented in the Visual Studio2012 environment and in the ASP.NET framework using C# language.The SQL Server2012 database and GeoDataBase were used to store spatial and non-spatial information, respectively. ArcGIS Server10.2 software was used to enter the maps on the system. At the end, according to the survey resultsobtained from people, about 80 percent of participants in the inquiry were satisfied with the designed system. Also, based on a survey results obtained from four experts of water organization, three of them were satisfied with the design of such a system.
Meisam Rostami; Ramin Kiamehr; Ramin Bayat
Abstract
Considering theproper and comprehensive criteria at the route locating stage can play a major role in reducing economiccosts, increasing safety and accessibility to roads and preserving the environment. For this purpose,several parameters such as Ground Elevation Model, land cover, demographic and tourism ...
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Considering theproper and comprehensive criteria at the route locating stage can play a major role in reducing economiccosts, increasing safety and accessibility to roads and preserving the environment. For this purpose,several parameters such as Ground Elevation Model, land cover, demographic and tourism information, how sunny the roads are during cold seasons, distribution of rivers and fault lines were considered for optimal routing of the Ilam-Homeil road in this research. In order to determine the inter-layer cost, a knowledge-based approach was proposed based on which, a cost function was considered for each of the layers in accordance with its characteristics and its way of influence on providing the goal. The main advantage of this approach isthat the cost variations are not merely linear for the existing data intervals in each one of the layers, and the characteristics of corresponding layer areincluded in the definition of relevant cost function. Next, the pair-wise comparison and Analytical Hierarchy Process (AHP) wereused, taking advantage of the experts’ opinions, for inter-layer weighting. Accordingly, the shortest routewas implemented throughcombining layers and the method of overlapping index by providing the lowest cost with 3 variables or different variants. In the first variant, the common methods (linearly) were used for inter-layer weighting. In the second variant, the only criterion used for determining the route was the slope criterion. The proposed method of knowledge-based weighting was applied in the third variant, taking into account all the criteria. Based on the results, less attention has been paid to factors such as distance from the fault lines and the rivers, access to population centers and tourist area in determining the constructed route, and the main criterion in routing has been the topography of the region alone. Also, the length of the route in all of the three variants is less than the length of the constructed route. In general, the route resulted from the application of knowledge-based weighting has a better statusin providing different criteria than the constructed route, as well as the two other variants.
Fereydoon Nobakht Ersi; Abdolreza Safari; Mohammad Ali Sharifi
Abstract
The main purpose of the present paper is to use the ARMA probability models to model the time series of the daily positions of GPS permanent station.Daily Locations of the LLAS permanent station in the Southern California region have been selected from the SCIGN network, covering a period of seven years ...
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The main purpose of the present paper is to use the ARMA probability models to model the time series of the daily positions of GPS permanent station.Daily Locations of the LLAS permanent station in the Southern California region have been selected from the SCIGN network, covering a period of seven years from January 2000 to December 2006, to establish a time series of position and to analyze it. Based on the time series of the daily position and using the weighted least squares, the geodetic parameters such as linear trend, annual and semi-annualfluctuations, as well as offsets,have been simultaneously estimated for the LLAS permanent station. In this study, Auto correlation Functions (ACF) and Partial Auto Correction functions (PACF) are used as the study tools for identifying the time series behavior of daily position of GPS permanent station and provide the possibility to examine the dependency of the position time series daily data. Given that several different probabilistic models may be appropriate for a daily position time series, therefore,the Akaike Information Criterion has been used at the stage of identifying and selecting the useful model. In this study, numerical results show that the best autoregressive moving average (ARMA) probabilistic model for the LLAS permanent station is ARMA (1, 1) for direction N. Also, the ARMA (2, 1) probabilistic model is the most appropriate model for direction E, while the ARMA (1, 2) probabilistic model is the best model for direction U. After estimating an appropriate probabilistic model for the time series of the daily position of the GPS permanent station, it is possible to predict the time series of the position along with the trend and seasonal components.
Davood Akbari; Abdolreza Safari; Saeid Homayouni
Abstract
Abstract Recently, a new approach, based on the Hierarchical SEGmentation (HSEG), grown from automatically selected markers using Support Vector Machines (SVM), has been proposed for spectral-spatial classification of hyperspectral images. The HSEG algorithm, which combines region object finding with ...
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Abstract Recently, a new approach, based on the Hierarchical SEGmentation (HSEG), grown from automatically selected markers using Support Vector Machines (SVM), has been proposed for spectral-spatial classification of hyperspectral images. The HSEG algorithm, which combines region object finding with region object clustering, has given good performances for hyperspectral image analysis. This technique produces at its output a hierarchical set of image segmentations. This paper aims at improving this approach by using image segmentation to integrate the spatial information into the marker selection process. In this study, the markers are extracted from the classification maps obtained by both SVM and watershed segmentation algorithm. The watershed algorithm is used in parallel and independently to segment the image. It is a powerful morphological approach to image segmentation. Moreover, the class’s pixels, with the largest population in the classification map, are kept for each region of the segmentation map. Lastly, the most reliable classified pixels are chosen from among the exiting pixels as markers. Then, a marker-based HSEG algorithm is applied. Each region from the segmentation map is classified by applying a majority vote rule over the pixel-wise SVM classification results. Three benchmark urban hyperspectral datasets are used for our comparisons: Pavia, Berlin and DC Mall. The results of our experiment indicate that, compared to the original hierarchical approach, the marker selection using segmentation algorithm leads in more accurate classification maps. Indeed, the proposed approach achieves an approximately 4%, 6% and 5% kappa coefficient higher than the original hierarchical-based algorithm for the Pavia, Berlin, and DC Mall datasets, respectively.
Monir Darestani Farahani; Mahdi Akhondzadeh Hanzaei; Farhang Ahmadi Qivi
Abstract
Abstract
Water salinity is one of the important environmental factors of the sea and plays a significant role in the study and prediction of the oceanic surface currents, location analysis of the fish aggregation, density determination and studying its changes, and also in ecological properties. This ...
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Abstract
Water salinity is one of the important environmental factors of the sea and plays a significant role in the study and prediction of the oceanic surface currents, location analysis of the fish aggregation, density determination and studying its changes, and also in ecological properties. This parameter changes greatly with time and location, and proper recognition of it requires measurements at short time intervals (monthly) of multiple points in the study area.
In traditional ways, the assessment and evaluation of one or several specific factors of water quality is often costly and time-consuming, and cannot be a good indication for the entire area of a vast region. But in recent years, satellite and remote sensing technology have been considered as an appropriate tool for evaluating some water quality parameters because, given the digitality of these data, their wide availability, regular measurements, their repetition in short periods of time, Less cost and time, a wide range of projects can be achieved. The purpose of this study is mapping sea surface salinity of the Persian Gulf in Iran and the Gulf of St. Lawrence in Canada using MODIS satellite imagery. In this regard, a software has been produced in Iran for the first time that can prepare salinity, temperature and density maps of the sea surface in three different models with proper accuracy by entering the MODIS satellite imagery and CTD field data. High capability and flexibility of the Artificial Neural Network in approximation of nonlinear and linear continuous functions in hybrid space, led this study to provide a new method based on using this network in which salinity map is determined by a multilayer perceptron network.
Ali Jozaghi; Abolfazl Shamsai
Abstract
Abstract
According to recent studies, in 2025, water shortages will increase in poor countries with limited resources and rapid growing populations; hence, a long term planning is necessary for saving water resources. One of the most important plans is building a dam onperennial rivers and the main ...
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Abstract
According to recent studies, in 2025, water shortages will increase in poor countries with limited resources and rapid growing populations; hence, a long term planning is necessary for saving water resources. One of the most important plans is building a dam onperennial rivers and the main step in this process is selecting the best place in watershed. The aim of this study is to develop the multi-criteria decision support framework for dam site selection in South of Sistanand Balouchestan province. A study has been made by applying GIS and Technique for Order Preference by Similarity to Ideal Solution, to select and prioritize potential places for constructing a dam. The criteria for dam site selection have been chosen upon scholars’ ideas and available data. They include Geology, Land use, Sediment, Water Quality, Erosion, Groundwater and Hydrology. Ratio Estimation Procedure has been used to estimate weight of criteria. First, TOPSIS method and GIS have been conflated and a geospatial layer has been createdthat is called “the relative closeness to the ideal solution” whose values are between zero and one. Second, A Model has been created based on streams and topographical conditions. This model evaluates structural height, crest length of dam, and volume of reservoirs. Then, upon the results of the model, 15 places have been selected. Finally, the sites have been prioritized by finding their values on the created layer. In conclusion, the best place is A - Kahir dam- whose value is 0.85, and the worst site is P,whose value is 0.47 as well as Pishin dam which is the worst dam amongst all the dams which have been built in the region with the value of 0.62. Also, the best option is K, that is located on the right side branch of Sarbaz Riverand its value is 0.67.
