Journal of RS and GIS for Natural Resources
Year:2011 | Volume:2 | Issue:3|Papers Count:9

DEM is needed for many branches of earth and environmental sciences such as control of erosion, flood planning, road construction, earth resource's recognition, and soil mapping. There are varieties of resources in generation of DEM, one of them is stereo satellite imagery. The objective of this research is the study of how to extract DEM from ASTER sensor stereo image. ASTER consists of three different subsystems: the Visible and Near-infrared (VNIR) and an additional backward telescope for stereo, the Shortwave Infrared (SWIR) and the Thermal Infrared (TIR). Each subsystem operates in a different spectral region, with its own telescopes, and is built by a different Japanese company. In addition, one more telescope is used to view backward in the near-infrared spectral band (band 3B) for stereoscopic capability. Images of Kashan area, which has been undulating topographic condition, were used. DEM extraction was based on the correlation algorithms between right image (3N) and left image (3B).The more correlation these tow images, the more precise DEM will be achieved. Finally, by correlation between tow images relative elevation attained. The results show that ASTER sensor, using along track imaging will attain the more precise DEM. The result accuracy of these images will be less than one pixel. This factor will improve the extraction of another production result by DEM.

There has been increasing tendency toward outdoor recreation due to negative effects of urbanization such as air and sound pollution. Desert areas are one of the most attractive ecosystems for nature-based tourism. There is a need for new methods for selecting suitable recreation sites as there are usually conflicts between the recreational requirements of tourists and the needs of wildlife species. We determined the most suitable areas for dispersed recreation in Abbasabad Wildlife Refuge using GIS-based Boolean and fuzzy methods with special attention to conservation concerns. At first step, the most important factors determining the suitability of a site for recreation were identified. These factors were weighted within an Analytical Hierarchy Process (AHP) and were then standardized by fuzzy functions. Habitats of threatened or rare species were ruled out from the suitable sites determined by fuzzy logic method. We suggest that fuzzy logic method is appropriate for identifying suitable areas for recreation, but the selected areas by this method should be rigorously checked against the biological needs and conservation status of the existing wildlife species.

The aim of this study was to evaluate the status of the soil criteria for assessment of desertification and comparison of soil criteria maps produced by kriging interpolation with maps produced by help of satellite imagery. Sampling took place in Segzi plain area in eastern Isfahan at a 76043 ha area and numerous indicators of soil samples were determined for each of 34 points. Indices scored based on MEDALUS method and using the geometric mean of indices of soil. The final map of soil condition was obtained from the reflection of different bands of satellite images and kriging interpolation method. The results showed that the percentage of organic matter, percentage of soil gypsum, electrical conductivity and sodium adsorption ratio, are the most important factors affecting the phenomenon of desertification. For soil indicator mapping by kriging, different interpolation methods were used and finally to produce each indicator map the highest accurate method was used. The statistical analysis showed a significant correlation between soil indicators and spectral data of red & green bands and brightness index, and consequently, it is possible to create soil indicator maps with these bands.Accuracy comparison of produced maps showed that maps derived from satellite images are more accurate at soil indicator mapping. The results of this study can be used in review and assessment of the desertification process in similar areas.

This study evaluation of relationship between slop-area and precipitation parameters involve amount, intensively and duration with sediment yield by gully erosion. The present study was taken place in Badreh watershed in Ilam province, Iran, in order to investigate the relationship between sediment yield from gully erosion and rainfall depth, intensities and duration and slop-area. For this purpose, 20 axial, frontal and digitized gullies were precisely selected, and their derange basin (slope-area) variations were surveyed at the beginning and end of six storm runoff events during November 2009 to May 2010. The consequential affecting factors were then determined with the help of factor and regression analyses. The results of the study showed that rainfall amount intensities were important factors controlling sediment yield by gully erosion and slop 2-5% were effective for its. The rainfall amount was then found as the best indicator for sediment yield based on discriminative analysis. A significant relationship was ultimately established between sediment yield and rainfall amount with the respective determination coefficients of 871 %.

Population growth and urbanization rate during recent years have led to an increase in demand of building, which. Consequently, causes changes in the land use/cover. Urban land use is one of the most important activities that changed the land surface leading to the modification of the receiving environment, so assessing urban growth provides valuable information for monitoring growth effects. Change detection is a technique used to reveal the changes in a particular object of study between two or more time periods. In this study, we determined spatial growth of Mashad City in north east Iran since 1987 to 2006 using TM and IRS_P6 satellite data. In doing so, a post classification comparison was used. We produced land cover maps through the years 1987 and 2006 with an overall accuracy of 86% and 91% respectively. The result of this study revealed that Mashad had expanded significantly over the 20 years of study. We found that the extent of the City increased from 74 km2 in 1987 to about 148km2 in 2006, with a growth rate of 5%. Most changes occurred in west and northwest of the City. We successfully assessed the past land use changes and offered information to identify the most effective factors that have brought about those changes.

Environmental crises' are created due to inappropriate pattern and conversion of land use. In this research, the land use planning map of Kachik's watershed located in Golestan province was prepared in ArcGIS 9.3 based on the current systemic module and two-hybrid methods in land-use planning. First, the final map of environmental units made by overlaying land form unit, soil type, isorain, geology and vegetation type maps.The map of land uses capability has made on the basis of evaluated 116 micro ecosystems. Then, land-use planning map has been made in the basis of comparing a qualitative method. The results showed that farm lands to have been exploited about 20 percentages. Furthermore, the studied region is unsuitable for urban development, while it has been potential for double afforestation (increasing of afforestation from 9.44 percentages to 16.30 percentages).

One of the most important issues in the use of wind energy determined the location of which has a great effect on the efficiency of wind power generation equipment. The purpose of this study was to determine the role of climate, geography, socio-economic, environmental and geological sites suitable for construction of wind power stations in the Khuzestan province. The role and impact of different restriction maps and map these factors were contributing factors. Weight criteria, alternative and sub-criteria options with standards processes in hierarchical analysis software EC 2000, was determined and the environment for modeling and spatial analysis and GIS software was used for data integration. The results show that the south, southwest, the North and West Khuzestan province the best places for wind power plants are constructed.

West of Iran has rich natural recourse such as forest and rangeland by have spatial weather. This recourse has been high changes in last decade by population growth and unusual uses. Marivan area is one of the cities that are in this location. In addition, Marivan has Zarivar Lake with different uses such as tourist attractions and spatial ecosystem. Aim of this study is the investigation of land use change detection in Marivan city by using TM and ETM+ sensors of Landsat satellite during 16 years (1989-2005) by Post classification method and ENVI4.7 Software. Results showed that during the period study 24.11 present of the land use has been changed. The most changes related to agriculture and forest land use (49.45 and 38.29 present). These changes have the reduction trend. The reason of agriculture land use reduction is given up dry land farming. On the other hand, residential land use increased during period study. Zarivar lake area was not important changes during study and this suggested establishment of lake area during period study.