Important Facts About Dem India

By Author: Bakul Sikri
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DEM or Digital elevation model is digital representation of a geographic region. The DEM model at times referred as digital terrain model or DTM. Precisely it represents topographical images of a particular place or area undertaken into consideration. The earth surface can be classified into different features such as highlands, Midlands and lowlands. Determining altitude from land surface is an arduous task and it requires creation of large number of land images. Accurate measurement of land altitudes is not possible due to land deformations. To determine the accurate height of land surface, various methods are used. Then these measurements are used to create DEM India or digital elevation model, which is help in getting detailed information on topographical studies. DEMs or DTMs technology also can be used to make representation of original maps, and square grids. These representations are mainly created by survey methods and remote sensing methods.
This system is generally used in geographic information systems, mainly for constructing digital relief maps. ...
... Remote sensing technologies are made possible to use easily with the DEMs. There are various other ways to produce DEMs. To create DTMs and DEMs models requires expertise and experience, thus precise techniques are used for creating DEMs. The most intricate and meticulous techniques used for creating DEMs are LiDAR, Stereo Photogrammetry, Real Time Kinematic GPS, Doppler Radar, Topographic Maps, etc. There are several companies in the market that offer digital elevation models services or computer aided architectural design. There are three steps followed for creating digital elevation models such as scanning and referring contour map, digitizing contours into micro station, and processing contours into a surface terrain model. These models are presented by companies in 2d cad drafting and 3d CAD drafting.
Along with these GIS and CAD companies offer services of taking Ortho rectified images. These types of images, which are take after ratifying pictures taken by satellite or image sensor. These images are also called Orthophoto Generation images. The images are taken after ratification of distortion in images in aerial photographs. The distortions in images are caused due to systematic sensor or platform, the ratification of distorted images is known as ortho rectification. This process is majorly used in Geographic Information System (GIS) industry. The images rectified with the help of ortho photo have uniform scale are used for assess correct distance. This process helps in getting accurate data and rectifies distortions in image created due to lens, sensor tilt, and various other reasons.