Academic & Law Serials


Volume 19 (1), Jan-June, 2014, pp.33-49


B. S. Manjare
Department of Geology, RTM Nagpur University, Nagpur (MS) India


DEM is suitable for representing the continuously varying topographic surface of the Earth and it is a common data source for terrain analysis and other spatial applications. DEMs are increasingly used for visual and mathematical analysis of topography, landscapes and landforms, as well as modeling of surface processes. Selection of suitable source of DEM and its resolution play important role in deriving the parameters. Relatively large DEM grid cells make up the model domain in order to reduce the computation time. This allows quick model calibrations and model sensitivity analysis. A major disadvantage of the use of low resolution input data is the loss of important small-scale features that can seriously affect the modeling results. If the input DEM is at a higher grid resolution, during the transformation or re-sampling of the original DEM data to a lower model resolution, important topographic details are lost mainly as a result of averaging. If the input DEM is already at a low resolution, it does not represent the actual on-ground topographic features, which might significantly affect the accuracy and reliability of the results from the modeling exercise. In applications of geographic information systems (GIS), provide opportunities for modeling, analyzing and displaying geographical phenomena connected with topography and relief. Much valuable information in the form of attributes related to the surface of a real terrain can be gained by interpretation of terrain models. Different DEMs of study area are generated form CARTOSAT 2.5 m resolution, ASTER 30 m resolution and SRTM 90 m resolution by using software ARC GIS 10.2. The analysis of the remote sensing data with conventional data and sufficient ground truth information makes probable to recognize and delineate the various ground features such as geological structures, geomorphological features and their characters. This study is an attempt to delineate the slope in and around Nagpur and Chindware Districts of Madhya Pradesh and Maharashtra by using Digital elevation models using integrated approach of Remote Sensing and GIS techniques. Digital elevation models (DEMs) by observing the elevation, aspect, slope and hillshade images. The present study area is the part of central India covering an area of about 710 sq. km. in the Nagpur district of Maharashtra and Cindwara district of Madhya Pradesh state. DEM has been an excellent supplementary information database for interpretations in the present study area along with other data. By comparing the CARTOSAT DEM 2.5 meter resolution with SRTM DEM 90 m and ASTER 30 mt. resolution. However the CARTOSAT DEM 2.5 m resolution is well utilized for the slope of any part of the earth surface.

Key words: CARTOSAT DEM, ASTER DEM and SRTM DEM, Chindwar, Remote Sensing and GIS.


Digital elevation models suggest the most widespread methods for extracting important elevation and topographic information. DEMs are used for visual analysis of topography, landscapes and landforms other than modeling of surface processes (Welch 1990). Nowadays GIS is being used in various purposes such as evaluation of surface features for geological and geomorphological studies. The contemporary computer technologies may provide additional tools for geological mapping which may improve better agreement of determination of geomorphological, geological, topographical and slope analysis with the terrain topography. One of such tools of GIS is the Digital Elevation Model (DEM) which can serve both as information source for finding geological boundaries, controlling elevations, and at the same time play important role in preparation of the base map as well as various surficial thematic maps (S. Ostaficzuk, 2005). It is also used for many purposes like providing flood and landslide risk zone, highways and corridor selection including cut and fill estimation etc. Currently Digital elevation models (DEMs) is considered as the main resource for the extraction of various geomorphologic and topographic features depending on their elevation, spatial distribution and deviations (Felicisimo, 1994). A DEM is a quantitative, three-dimensional representation of the earth surface derived from elevation data. It provides basic information regarding terrain characteristics. The primary attributes, which can be derived from the DEMs, are slope, aspect, profile curvature and catchment area. The secondary attributes, which can be derived from a DEM, are upslope area, topographic index, stream power index, radiation index and temperature index (Wilson et al., 2000). A DEM is typically given in one of the three formats: the raster-based grid DEM, the vector-based Triangular Irregular Network (TIN) and contour-based storage structure. The TIN is considered to be a primary (measured) DEM while the grid DEM is considered to be a derived (secondary) DEM (Toppe, 1987). Slope can be regarded as the outcome of active processes sloping passive materials with depending on the time during which the processes have operated. Slope can be identified in term of structure, processes and stage as outlined by Davis (1899). A more realistic approach is to view slope as numerous and complex linkage between factor, processes and forms.

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