Production of Digital Elevation Model of Marvdasht Plain Using ENVISATASAR Radar Images with C-Wavelength Comparison with GPS Points and ۱:۲۵۰۰۰ Topographic Maps of South Zagros Region

Digital Elevation Model is a continuous statistical representation of the earth by a large number of selected points with known coordinates of length, width and height. The use of three-dimensional models of the earth's surface has a wide range of applications in many areas of research and implementation. It is high and the areas are level. All the resulting points have a height above sea level. Most GIS spatial analyzes use elevation data such as DEM. Using it, you can prepare a slope map and slope direction and perform various analyzes in three dimensions. Most of the time, DEM is also used as the bottom view of the maps. Elevation is used to extract height and height data. Major users (DEM) in the fields of civil engineering, surveying and photogrammetry, earth sciences, water resources management, military applications, telecommunications, urban planning digital land models as one of their information layers to achieve management, executive goals or produce new products using location-based. In this study, using images of ASAR ENVI SAT sensors in C band in the study area, we prepared a digital elevation model and then compared. And for verification, we compared this prepared model with the existing topographic maps at the scale of ۱.۲۵۰۰۰ as well as the fixed points of GPS stations and also with the digital model obtained from (SRTM) in terms of elevation. The results of radar image processing in C bands of ENVI SAT ASAR sensor and its comparison with the data of the surveying organization indicate that the data processed from C band gives more favorable results and close to the ground control points, but considering Due to the correlation between GCP points and DEM obtained from topography, production conditions using satellite images are not favorable for the region. GCP captured the height points of radar images are in better and more favorable conditions according to Table (۴) which shows the standard difference and this indicates the superiority of radar images for DEM production. Digital model comparison ratio with topographic points, shows the accuracy of satellite images in flat areas. In mountainous areas, due to the inclination of the points and creation of incoherence points, it is not continuous shadow and the level curve lines are intermittent.

Keywords:

Digital DEM Altitude Model , Interference Measurement , GCP & GPS Points , C band , Sensor ASAR