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.
Alireza Azmoudeh Ardalan (Translation)
Volume 3, Issue 12 , February 1994, Pages 6-8
Abstract
The Global Positioning System (GPS) is the world's leading position-determining means around the world at all the hours of the day, in different atmospheric, space, sea and land conditions. Currently, there are 10 satellites of the GPS’s block 1 in the orbit for testing the system and land receivers. ...
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The Global Positioning System (GPS) is the world's leading position-determining means around the world at all the hours of the day, in different atmospheric, space, sea and land conditions. Currently, there are 10 satellites of the GPS’s block 1 in the orbit for testing the system and land receivers. Many of these receivers are operating beyond their predicted lifetime. Two satellites from this group are out of activity and one is about ending its mission. The Challenger Spaceship Crash postponed the full deployment of the satellites of Block 2 for nearly two years. According to the latest decision, the first launch of block 2 satellites was carried out in the fourth quarter of 1988 (Jewkes, 1987), and, according to a predetermined schedule, complete deployment of the block 2 satellites was completed by the end of 1991.
The initial design of the system was based on a 24-satellite system, which was later reduced to 18 active and 3 reserve satellites due to financial issues. The calculations show that the recent system (18 satellites), despite all the efforts made to give it the best geometric status, leads at each moment to the creation of four areas on the ground in which the act of position determining takes place with poor quality. These areas are called “Outage”. The extent, location and time of this state vary as a function of time, but can be precisely predicted. In areas where this situation is created, temporary use of other navigation devices is recommended.
Ramin Kiamehr
Volume 3, Issue 12 , February 1994, Pages 9-13
Abstract
One of the methods for determining the seismic pattern in space and time is to study the occurrence of strain by registering changes in the Earth's Crust constantly using geodetic monitoring networks and satellite and spatial observations. In this paper the method of analysis of movement in geodetic ...
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One of the methods for determining the seismic pattern in space and time is to study the occurrence of strain by registering changes in the Earth's Crust constantly using geodetic monitoring networks and satellite and spatial observations. In this paper the method of analysis of movement in geodetic networks by GPS method is described in detail, and, while highlighting the important points in GPS satellite observation planning, the accuracy necessary for these issues, the advantages of using this method and finally the method of strain analysis and obtaining the maximum shear and dilatation parameters in order to interpret the displacement in these networks by finite difference and finite element methods are described in detail.
Hosein Shokri Komsari (Translation)
Volume 3, Issue 12 , February 1994, Pages 14-17
Abstract
This paper describes the experiments conducted concerning production and revision of maps and the use of satellite images in Germany.
Since 1976, using satellite imagery, photogrammetric products on a scale of 1: 500,000 to 1: 50,000 have been produced. In the past few years, we obtained a high resolution ...
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This paper describes the experiments conducted concerning production and revision of maps and the use of satellite images in Germany.
Since 1976, using satellite imagery, photogrammetric products on a scale of 1: 500,000 to 1: 50,000 have been produced. In the past few years, we obtained a high resolution (5 to 10 meters) from Russian satellite images taken using the KFA-1000 camera. Experiments have shown that these photos are suitable for revising maps on scales from 1: 25,000 to 1: 50,000.
Mohammad Mosayyebi
Volume 3, Issue 12 , February 1994, Pages 18-24
Abstract
Golpayegan is one of the cities of Isfahan province, located 180 km northwest of Isfahan city and 350 km southwest of Tehran.
The altitude of the city of Golpayegan is about 1818 meters and the average height of the Golpayegan watershed is 2122.1 meters above the sea level, and 63 percent of the of ...
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Golpayegan is one of the cities of Isfahan province, located 180 km northwest of Isfahan city and 350 km southwest of Tehran.
The altitude of the city of Golpayegan is about 1818 meters and the average height of the Golpayegan watershed is 2122.1 meters above the sea level, and 63 percent of the of the area of the basin has an altitude greater than 2100 meters (Figure 1). Therefore, Golpayegan Basin is considered as one of the highlands of Iran, in which the frosts are long-lasting and their danger period throughout the basin is 7 months. Snowfall is one of the typical features of Golpayegan’s climate, and from late November on its precipitation possibilities are high and in most of the years the area is covered with snow throughout the winter. For this reason, the people of the Golpayegan region have developed interesting beliefs and ideas about these matters, and they use terms whose study can help understanding the climatic realities of the basin and traditions and cultural elements of the people of the region.
The author attempts to elucidate the beliefs of the people of the Golpayegan region concerning snow and frost, and to combine it with scientific subjects. Perhaps, in this way, there can be a passing point to the climate and environmental issues caused by snow and frost as well as the popular culture of people in this regard.
Peter Grego
Volume 3, Issue 12 , February 1994, Pages 25-27
Abstract
Full lunar eclipse is one of the most interesting scenes in astronomy. Until now, not two of the observed lunar eclipses have been completely similar. All solid heavenly bodies, which receive light from the sun, create a shadow in space. The extent of this shadow depends on the size of the mass and its ...
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Full lunar eclipse is one of the most interesting scenes in astronomy. Until now, not two of the observed lunar eclipses have been completely similar. All solid heavenly bodies, which receive light from the sun, create a shadow in space. The extent of this shadow depends on the size of the mass and its distance from the sun. There are two main elements in these shadows, which are Umbra and Penumbra.
Robin Crodd
Volume 3, Issue 12 , February 1994, Pages 28-34
Abstract
Launching into space The countdown is running out. Check seat belts, attachments and connections. Five-four-three-two-one-zero- with hearing a tremendous sound, feeling the heat of rockets, we pass their fire, and start the journey into space. In less than a minute, the clouds are split and the sky changes ...
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Launching into space The countdown is running out. Check seat belts, attachments and connections. Five-four-three-two-one-zero- with hearing a tremendous sound, feeling the heat of rockets, we pass their fire, and start the journey into space. In less than a minute, the clouds are split and the sky changes from blue to black. As the rockets work, it speeds up and goes up, and when they stop, we are in space.
Abbasali Salehabadi (Translation)
Volume 3, Issue 12 , February 1994, Pages 35-48
Abstract
Two separate types of flights were made in Finland to determine how the position of the aerial camera is determined by the GPS system. The first test flight was conducted for a small block under adverse weather conditions, with the results indicating a high potential for GPS in modifying the block through ...
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Two separate types of flights were made in Finland to determine how the position of the aerial camera is determined by the GPS system. The first test flight was conducted for a small block under adverse weather conditions, with the results indicating a high potential for GPS in modifying the block through the “Bundle Block Adjustment” analytical method. The second flight was a fully functional and justified flight that was performed on an average-level flight block, which, despite the usual issues confronted in this block, the results were very satisfying. Air triangulation carried out by satellite data was very good and satisfactory for preparing maps of 1: 5000 and smaller scale by GPS kinematic method in Finland. On the other hand, the number of control points that can be considered for it is considerably reduced, and this leads us to save money and time compared to the usual classical approach.
Pirooz Mojtahedzadeh
Volume 3, Issue 12 , February 1994, Pages 49-56
Abstract
The Masandam Peninsula is the closest Arabic land in the neighborhood of Iran, and yet the most unknown Arab neighbor on the other side of the Persian Gulf. The northernmost point of Masandam is only 39 km away from the southernmost part of Iran in the Strait of Hormuz (Khark Island), and at least half ...
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The Masandam Peninsula is the closest Arabic land in the neighborhood of Iran, and yet the most unknown Arab neighbor on the other side of the Persian Gulf. The northernmost point of Masandam is only 39 km away from the southernmost part of Iran in the Strait of Hormuz (Khark Island), and at least half of the people in Masandam are originally Iranians. However, Iranians’ knowledge of these people and their land is very little.
Alireza Owsati
Volume 3, Issue 12 , February 1994, Pages 57-64
Abstract
Today, undoubtedly, the basis of the preparation of topographic maps can not be understood as independent from the use of satellite imagery, since these images provide humanity with valuable information for the preparation of maps and other information on land features used during the process of making ...
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Today, undoubtedly, the basis of the preparation of topographic maps can not be understood as independent from the use of satellite imagery, since these images provide humanity with valuable information for the preparation of maps and other information on land features used during the process of making maps. In order to prepare maps on very large scales (1: 1000 and larger) as well as on relatively small zones, it is also possible that methods that are based on measurement and interpretation of satellite images be employed rather than classic methods of surveying. In any case, even when such images are taken as bases of the creation of topographic maps, As long as the land surveying methods are not carried out to create control points, collect names and information and determine boundaries (which are integral parts of the preparation of topographic maps), classify land features that can not be determined on the images, and complete some map features that are covered by plants, buildings or shadows, these maps can not be of particular and reliable significance.
In the mapping projects, the quality that makes the map sufficiently valid is the comprehensive and useful information that is transmitted through the map to the user. In fact, 95% of the total efforts made in the process of making maps is directed toward this goal, so it is not irrelevant to mention a brief overview of the special features of topographic and thematic maps reflected in Table 1. Topographic maps and equivalent modern maps include collections of digital tantamount data that not only can be considered as valuable products in their own regard, but also as the basis for other types of thematic maps created using images from telework. In the United Kingdom alone, we find large governmental surveying agencies, including the ordnance Survey or the Directorates of overseas or Military Surveyors, which use a large number of employees to prepare topographic maps. In addition to the aforementioned companies, there are many private agencies active in the same field that seek to meet the needs and advancement of the goals of engineers, designers, architects, oil and mining companies, etc. All these companies widely use satellite imagery to advance their intentions.
