It not only provides the data with greater accuracy and quality but also has a quick turn-around time. Digital Elevation Models have now become popular to derive land information for various purposes. NASA’s Mars Digital Terrain Model and the Mission Experiment Gridded data record from the Mars Orbiter Laser Altimeter instrument of Mars Global Surveyor provides with crucial information on the terrain formation of the planet. With the increasing advancement in the space sciences DEMs are used for the study of the terrains of other planetary objects like that of the Mars and the moon. Hence, we now can conclude that DEM is not just limited to the study of the earth’s surface any longer.
#DIGITAL TERRAIN MODEL IN FLOOD MONITORING FREE#
ALOS provides a free global DSM with 1arc second resolution and a commercial DSM/DTM with 5meter resolution.TerraSAR-X and RanDEM-X provide DEM in the form of a uniform global coverage with a 12m resolution.The Radar Satellite RADARSAT-2 has been used to provide DEMs for military and commercial purposes.The Global Multi-resolution Terrain Elevation Data 2010 (GMTED2010) combines SRTM data and that outside the coverage of SRTM to provide information at 7.5 arcs Second resolution.EARTH2014 global topography and relief model provide information on ice sheets heights and bedrock over Antarctica and Greenland with grids at 1 arc-min resolution.Combining topography and Bathymetry yields the truly Global Relief Model and also, SRTM30Plus combines GTOPO30, SRTM and Bathymetric data to yield a truly Global Elevation model Bathymetry or Submarine elevation data is obtained from ship-mounted depth soundings.It covers 99% of the globe and represents elevation at 30-meter resolution. The Advanced Spaceborne Thermal Emission and Reflection Radiometer of the Terra Satellite provide a higher quality DEM which is also available free.But the quality of the representation is variable and some areas are very poor. GTOPO30 provides a free DEM of the whole world and is approximately 1Km along the.Creation of raised maps for relief or strategic land survey.Modeling Soil wetness with cartographic DTW-index.Extracting water flow information for hydrology or mass movement like landslides.Deriving terrain parameters for geomorphology.Rectification of 2D imagery from UAV or satellite.The common types of DEMs include DSM, DTM, Point Cloud and 3D. Sampling density Different types of DEMs.Interpolation and terrain analysis algorithm.Vertical and grid resolution or pixel size.There are various factors that influence the quality of DEM. It is just like that the imagery terrains come in different flavors depending on the need. Accuracy is independent of posting, but the tighter the posting the better the accuracy. Accuracy refers to how closely the heights in the model match the actual ground heights that you are measuring. The tighter the posting the more detailed terrain can be derived. It describes the distance between the measures of elevation on the ground. Generally posting is used for the name of the value of the DEM. There are two main factors that influence a digital elevation model namely Posting and Accuracy. DEMs are used in many fields, few of which are hydrological and geological analysis, hazard monitoring, exploration for natural resources and agricultural management.
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