Terrain Mapping

Terrain rasters are heavily used in GIS for a variety of purposes. Terrain is a part of analysis for just about any type of construction; buildings, roads, trails, freeways, and especially canals. Terrain is also critical to understand water runoff and flooding. Within biological sciences we use terrain to determine which areas are more suitable for plants such as the north or south side of a ridge.

Types

The most basic type of terrain raster is a "Digital Elevation Model" or "DEM". Within a DEM, each pixel contains the average (mean) elevation of the land the pixel covers.

DEM of Mt. Hood, Oregon

From DEMs, we can derive other types of terrain rasters including:

• DEMs
• Contours
• Slope
• Aspect
• Hillshades
• Viewsheds

Interactive Cross Section of DEM

Note: the tool below requires installation of a program on your computer.

Additional Resources

Wikipedia - Digital elevation model

National Elevation Dataset (USGS)

Test Your Knowledge

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