Digital elevation models (DEMs) represent the bare earth topographic surface digitally. The document discusses DEMs, including what they are, common data sources like SRTM and NED with their resolutions, and applications like estimating elevation and slope, determining drainage networks and watersheds, and using DEMs in hydrological modeling. DEMs are frequently used in terrain analysis, hydrology modeling, creating relief maps and contour maps, and 3D visualization and flight planning.

1. TOPIC-DIGITAL ELEVATION MODEL
Presented By-
ANURAG GHOSH (UID- 21143031026)
M.Sc. in Geo-informatics 2nd Semester
DATE-18/07/2022
PANDIT RAGHUNATH MURMU SMRITI MAHAVIDYALAYA

2.  Introduction
 What is DEM
 DEM data download source
 DEM data resolution
 DEM applications
 Use of DEM data
 Hydrological model use of DEM data
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3. Digital Elevation Model is the simplest form
of digital representation of topography.
DEM is frequently used to refer to
any digital representation of a topographic
surface.
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4. A DIGITAL ELEVATION
MODEL (DEM) IS
A REPRESENTATION OF
THE BARE GROUND
(BARE EARTH)
TOPOGRAPHIC
SURFACE OF THE
EARTH EXCLUDING
TREES, BUILDINGS, AND
ANY OTHER SURFACE
OBJECTS.
Digital
Elevation
Models (DEM)
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5. DEM
DSM DTM
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6.  Bhuvan
 Space Shuttle Radar Topography
Mission (SRTM)
 National Elevation Dataset (NED)
 ASTER Global Elevation Data
 Global Multi-resolution Terrain
Elevation Data 2010 (GMTED) 2010
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7. DEM data resolution
 SRTM data resolution = 30 meters, 90 meters
 NED data resolution = approximately 30 meters
 ASTER data resolution = 15 meters to 90 meters
 GMTED data resolution = 7.5 meters, 15 meters and 30 meters
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8. DEM applications
o Estimating elevation
o Estimating slope and aspect
o Determining drainage networks
o Determining the watershed
o Terrain stability
o Soil mapping
o To create a profile graph from digitized features of a surface.
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9. Use of DEM
 Hydrology modelling
 Creation of relief maps
 3D visualization
 3D flight planning
 Surface analysis
Contour map
Relief map
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10. Hydrology model use DEM data
1. DEM data
2. Extract
Study Area
3. Flow
Direction
4. Flow
Accumulation
5. River Basin
6. Stream
Order
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11. Method of stream ordering
SHREVE METHOD
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