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 22 , August 1997, Pages 4-6
Abstract
Remote sensing is a science that provides valuable information on objects and land features by measuring distances from afar and without physical contact.
In remote sensing, information can be obtained by measuring and recording the reflections of electromagnetic waves of atmosphere and ground level, ...
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Remote sensing is a science that provides valuable information on objects and land features by measuring distances from afar and without physical contact.
In remote sensing, information can be obtained by measuring and recording the reflections of electromagnetic waves of atmosphere and ground level, which are received by sensors installed on satellites, and after their analysis, the necessary information is extracted.
There are three major factors of reflection, absorption and passage in the collision of electromagnetic waves with any phenomenon, each of which depends on the wavelength of radiated energy and physical and chemical properties of the phenomenon, and the energy reflection from any phenomenon on the Earth is a function of wavelength, molecular and intracellular properties of the phenomenon and other physical characteristics of the objects under measurement. The satellite data originally contains various geometric and radiometric errors that are affected by satellite, sensor and atmospheric conditions, as well as errors in recording, transmission of information and other related issues.
Satellite data become valuable and useful after making geometric and radiometric corrections. By performing geometric corrections, satellite information is readily to for analysis and utilization.
Hamid Malmirian (Translator)
Volume 6, Issue 22 , August 1997, Pages 7-18
Abstract
The progress made over the past three decades in cartography, remote sensing and geographic information systems is due to the necessity of establishing new connections among currently specified technical regulations. Great efforts have been made to realize desirable collection of various cartographic ...
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The progress made over the past three decades in cartography, remote sensing and geographic information systems is due to the necessity of establishing new connections among currently specified technical regulations. Great efforts have been made to realize desirable collection of various cartographic data and more successful utilization of remote sensing data of regional and international data banks.
The importance of remote sensing as an environmental information sub-system has significantly increased by launch of a number of new satellites equipped with electronic sensors and images able to present data and pictures from physical and human elements of earth’s atmosphere.
Cartographic display of spatial and temporal changes of the earth’s elements is the most important goal of thematic cartography. This goal has been confirmed by many cases of planning for map preparation on global, regional and local scales. Thematic map production has been recognized by many associations as a vital task in exploration of underground resources and environmental management and planning. The rapid progress of satellite systems has led to expansion of remote sensing and its applications in cartographic and map-completion activities.
The connection between cartography, remote sensing and geographic information systems can be indicated in various ways. It seems that the Fig.1-1 reflects the connection among the three systems without presence of special governing regulations.
Abdolazim Ghanghermeh
Volume 6, Issue 22 , August 1997, Pages 19-22
Abstract
Caspian Sea is the largest lake on earth and its normal surface is lower than the free water level of oceans. It is surrounded by the five countries of Islamic Republic of Iran, Azerbaijan, Russia, Kazakhstan and Turkmenistan. Therefore, this sea is of special economic and political importance for these ...
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Caspian Sea is the largest lake on earth and its normal surface is lower than the free water level of oceans. It is surrounded by the five countries of Islamic Republic of Iran, Azerbaijan, Russia, Kazakhstan and Turkmenistan. Therefore, this sea is of special economic and political importance for these countries as well as other countries of South Asia. Currently, what has concerned these countries about their coastal lines is the advance of water toward their shores since 1977. In this regard, it has been tried to provide a brief discussion about the fluctuating behavior of the sea to determine whether there have been examples of this behavior with such strength in the past, or it is an exceptional state of water surface behavior. Do these fluctuations follow the rules of cyclical behavior common to other phenomena in the nature?
It is hoped that in this way a solution will be found for problems in coastal protective and preparatory planning. In this article, the relationship between climate change and fluctuating behavior of sea level is examined, and then a pattern for describing this behavior in historical periods is proposed.
Abbas Khosravi (Translator)
Volume 6, Issue 22 , August 1997, Pages 23-27
Abstract
This paper is an example of combination of GIS and remote sensing methods by scientists of Scott Institute of Polar Research in Cambridge, England during their study of ice covers in Nordaustlandet, Svalbard Archipelago in the north of Norway. Vast, remote polar areas are usually studied by remote sensing ...
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This paper is an example of combination of GIS and remote sensing methods by scientists of Scott Institute of Polar Research in Cambridge, England during their study of ice covers in Nordaustlandet, Svalbard Archipelago in the north of Norway. Vast, remote polar areas are usually studied by remote sensing methods. The above-mentioned project was implemented as a part of the European Space Agency’s program for study of ice caps and glaciers. Using GIS and whole range of remote sensing techniques, glaciological issues concerning different levels (different formations such as dry and wet snow or dry ice) on ice caps in an area in the north of Norway between latitudes of northern 74 to 81 degrees were studied.
Shahriar Khaledi
Volume 6, Issue 22 , August 1997, Pages 27-33
Abstract
Today circulation of water on earth, amounting to about 500,000 billion cubic meter, is well recognized by experts in the field despite its all complexities. Experts show great interest in examination of water circulation and determination of quantities of different water flows (precipitation, rivers, ...
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Today circulation of water on earth, amounting to about 500,000 billion cubic meter, is well recognized by experts in the field despite its all complexities. Experts show great interest in examination of water circulation and determination of quantities of different water flows (precipitation, rivers, lakes, aquifers, etc.) which form the totality of the earth’s water. Currently the issues concerning natural water resources are also studied. Generally, distribution of fresh waters around the world is very irregular, so that they might be completely inaccessible exactly where there is need for great amounts of such waters. For some fundamental reasons, if water resources are renewable, they are considered as among flows and in certain cases follow global scales. But in some countries, there are significant resources of unrenewable water, just as hydrocarbon and mineral resources. Numerical assessments of volume of water resources have been carried out on different scales and according to different parts of hydrosphere, and have revealed significant exploitation of such resources; these studies included oceans, polar ices, underground waters, soil moisture, lakes, rivers and atmosphere. M.L. l’Vovich has calculated the average periods of renewal of the above resources as follows: Oceans: three thousand years; aquifers: four to five thousand years; ice coverage, polar ice and continental glaciers: eight thousand years; lakes: seventeen thousand years; soil moisture: one year; rivers: almost twelve days; atmospheric humidity: one week. In absolute conditions, underground water is almost in correspondence with natural circulation of water. However, mineral resources take very long periods of time for renewal. Therefore, they can be considered as unrenewable on human life-span scales.
Piruz Mojtahedzadeh
Volume 6, Issue 22 , August 1997, Pages 34-37
Abstract
The land of Oman was called “Mazun” before Islam. Its entrance from Iran, namely the conical peninsula including the United Emirates and northern Oman was called “Mazundum”. This name is still used as “Masandam” for referring to the small peninsula at the northern ...
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The land of Oman was called “Mazun” before Islam. Its entrance from Iran, namely the conical peninsula including the United Emirates and northern Oman was called “Mazundum”. This name is still used as “Masandam” for referring to the small peninsula at the northern end of the United Emirates and northern Oman. This is the reason why the author uses the term “Mazundum” or “Masandam” to refer to whole the peninsula containing the United Emirates and northern Oman.
The term “Mazundum” or “Masandam” is an Iranian compound word, and the suffix “dam” in this compound is the same which has been used since ancient times by Persians to refer to a certain time or place. The name “Oman” existed in Sassanians’ time as “Umana”, and the port of Sohar in Oman was called “Masun”.
Sadegh Ahadian
Volume 6, Issue 22 , August 1997, Pages 48-51
Abstract
One of the ways studied in different countries of the world, especially the United States, to lessen the problems facing in ground transportation of goods, is the hydraulic transportation of agricultural and industrial products. Certain discoveries since 1950’s led the scientists to gradually realize ...
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One of the ways studied in different countries of the world, especially the United States, to lessen the problems facing in ground transportation of goods, is the hydraulic transportation of agricultural and industrial products. Certain discoveries since 1950’s led the scientists to gradually realize that if chemical substances are present in a liquid in two different phases in terms of chemical compounds so that they cannot be merged, they can be transferred together through a pipe from one place to another. Later, vast research was conducted on this subject, and in recent years the related research has been mainly carried out at the Missouri State University in the United States, with the result that by certain floating containers made through a special method, it is possible to transfer agricultural and industrial products through pipes. In the following, a summary of research and modeled examples of the above-mentioned system, carried out by two Iranian and Chinese researchers, Nikdeh and Li in the Missouri State University is presented.
In the second section of this paper, transfer of materials without energy is examined.
Saeed Sadeghian
Volume 6, Issue 22 , August 1997, Pages 52-61
Abstract
Data related to features of the earth’s surface have applications in many activities concerning planning, control and management of ground resources and man-made features. Data of this type are usually displayed on maps that show information on a reference plane. It is highly necessary that data ...
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Data related to features of the earth’s surface have applications in many activities concerning planning, control and management of ground resources and man-made features. Data of this type are usually displayed on maps that show information on a reference plane. It is highly necessary that data be ground-based, because it makes matching and combination of different sets of data possible.
A satellite image or photo provides an excellent outlook of a broad area of earth, thus presenting a comprehensive view of important physical and cultural features. Such images can be the best available data about many inaccessible areas of earth for which there are yet no reliable maps. However, a crude satellite image has defects such as distortion due to change of altitude, position of sensors, differences of altitude, earth’s spherical shape and lack of display of all features important for users. Consequently, in order to make best use of satellite images, data must be processed to remove distortions, extract three-dimensional information and practice interpretation of images for determination of type and use of features. Information obtained from other sources make completion of maps possible. Furthermore, by creating a network for displaying information system of national coordinates, the necessary consistency between the produced maps and other digital maps and data such as those available in a geographic information system can be realized.
Khosro Khajeh (Translator)
Volume 6, Issue 22 , August 1997, Pages 62-64
Abstract
In recent years, the developments in creating and extracting spatial data have led to emergence of operational tools in the form of geographic information systems. It is these developments that have opened our eyes to infrastructural issues about the manner and reasons of these systems’ operation. ...
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In recent years, the developments in creating and extracting spatial data have led to emergence of operational tools in the form of geographic information systems. It is these developments that have opened our eyes to infrastructural issues about the manner and reasons of these systems’ operation. What is a geographic information system? A tool? A piece of a software? Or a complex system involving software, hardware, people and organizations?
What is the difference between the newly coined terms of “geomatics” and “geo-automatics”? do they have the same meaning or are they different? Some of these questions have been answered clearly. Some of them raise more fundamental issues. Nevertheless, the common aim of all these discussions is spatial data and information.
Today, geo-informatics, geomatics and GIS are frequently applied, but they should be viewed in light of developments in creation and extraction of spatial data over the past three decades.
