# Terrain Analysis

Terrain Analysis is the analysis and interpretation of topographic features through geographic information systems. Such features include slope, aspect, viewshed, elevation, contour lines, flow, upslope flowlines and dowslope flowlines. The intention is to build mathematical abstraction of surface terrain in order to delineate or stratify landscapes and create an understanding of relationships between ecological processes and physical features [1]. Terrain analysis is frequently used in military operations to understand how physical geography affects combat[2].

Relief map of Sierra Nevada Range.

## Slope

Main articles: Slope

Slope measures the change in elevation over the change in horizontal position.

$m = \frac{\Delta y}{\Delta x}.$

## Aspect

Main articles: Aspect

Aspect is defined as the horizontal direction of the slope of topographic feature.

## Viewshed

A viewshed is the visible area by a human eye from a given location [1]. This can applied for line-of-sight for cell or radio towers and look-out stations.

## Elevation

Main article: Elevation

Elevation refers to the vertical distance above a fixed points, most commonly sea level.

## Contour Lines

Main article: Contour Line

## References

1. Deng, Yongxin; Wilson, John P; Gallant. "Chapter 23". The Handbook of Geographic Information Systems. 417.
2. Richbourg, Robert; Olsen, Warren K (1996). "A hybrid expert system that combines technologies to address the problem of military terrain analysis". Expert Systems with Application. 11:2.