Module 8 - Application in GIS - Least-Cost Path and Corridor Analysis

In the last regular lab for Application in GIS this term, we worked on least cost paths and corridors.  This is somewhat similar to suitability analysis, in that we can assign weights and values to various criteria, then combine them to obtain a final best result.

Instead of suitability, we refer to "cost" in this type of study.  Cost can be time, or money, or anything else we must expend to get from a source to a destination.

In this type of analysis, a cost surface is computed, and from that a cost-distance surface.  The latter calculates the cells of a raster that are easiest to travel across, based on the criteria, from a source to a destination.  We can then produce an ideal path across the surface that will incur the minimum cost of travel.

A corridor can also be found from one place to another.  Instead of a single, one-cell-wide path, the corridor is a zone of lesser cost.  We can specify a  threshold to define the corridor, saying that only costs below a certain value are desirable.  The map here shows a movement corridor for black bears between two areas of National Forest in Arizona.  The criteria for finding the corridor were land cover type, elevation, and distance from roads.  The green area on the map shows the most optimal area through which the bears can travel from either direction, between the two tracts of National Forest.