Finding the least cost path

Least cost path (LCP) analysis is the raster equivalent of network analysis, which is used to find the optimal path between two points in a raster. In this recipe, we'll perform LCP analysis on a digital elevation model (DEM).

Getting ready

You need to download the following DEM and extract the ZIP file to your qgis_data/rasters directory: https://geospatialpython.googlecode.com/svn/lcp.zip

How to do it...

We will load our DEM and two shapefiles consisting of start and end points. Then, we'll use GRASS through the Processing Toolbox to create a cumulative cost layer that assigns a cost to each cell in a raster based on its elevation, the value of the other cells around it, and its distance to and from the end points.

Then, we'll use a SAGA processing algorithm to find the least cost path between two points. Finally, we'll load the output onto the map. To do this, we need to perform the following steps:

1. First, we'll import the QGIS processing...