A 'Digital Elevation Model' (DEM) is used in GIS for:
Choose the correct answer
Only road network data
Terrain analysis: slope, watershed delineation, viewshed, flood mapping, earthwork volumes — derived from elevation grid
Attribute data tables only
Only underground utilities mapping
Correct Answer
B. Terrain analysis: slope, watershed delineation, viewshed, flood mapping, earthwork volumes — derived from elevation grid
Why is this the answer?
DEM: raster representation of terrain elevation (one elevation value per grid cell). Applications: (1) Slope and aspect maps; (2) Watershed delineation (flow direction, flow accumulation, stream network extraction); (3) Viewshed analysis; (4) Solar radiation modelling; (5) Volume calculation for earthworks; (6) Flood inundation mapping. Sources: SRTM (90/30m), ASTER (30m), LiDAR (< 1m), Cartosat DEM (30m).
Related Surveying MCQs
More solved Surveying questions for AE/JE Civil Engineering exams.
- 'Contour interval' selection for a topographic survey depends on:
- The 'EDM' (Electronic Distance Measurement) instrument measures distances using:
- The 'photogrammetric control' (ground control points) in aerial survey are required for:
- The 'corrections' applied to measured chain/tape lengths include all EXCEPT:
- The 'photogrammetric stereomodel' from two overlapping aerial photos allows...
- The 'levelling staff' reading is corrected for 'curvature and refraction' by the formula:
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