Introducing Geographic Information Systems with ArcGIS: A Workbook Approach to Learning GIS, 3rd Edition

Calculating a Least-Cost Path from “A” to “B”

In the following steps, you will find the least-cost path between a starting cell and a destination cell. You have probably noticed that you could figure out the least-cost path by investigating the direction raster. If so, you will have certainly noticed that doing so was a total nuisance. In the next steps you will generate a polyline featureclass that will show you the least-cost path from a given, specified cell to a “source” cell.

The software can handle multiple cells in both the starting raster and the destination raster, but this exercise will demonstrate the request using only one cell in each. If it has not become clear by this point, I should state the obvious: The cost (and/or the path) of going from A to B, as calculated by the raster manipulations you have been directing, is the same as the cost (and/or the path) of going from B to A. There are certainly instances in which this assumption is not warranted. One example would be if A is at the bottom of a mountain and B is at the top. Another example is driving in a city that has one-way streets. But the tool can be useful anyway.

The goal of this exercise is to use Shortest Path to create a polyline that shows the least-cost path between the single cell in a raster called Single_cell and the cell in the raster Onecell. You could, of course, determine this path by exploring the destination raster, but instead we will generates a raster based on least cost, then create ...