How can I find the least-cost-paths between a network of several points using QGIS or other easily available tools? That is, the easiest way to get from each point to every other point in the network, as opposed to just between one start and one end point.
The start and end points are polygons scattered unevenly across the map, and the intervening landscape is a patchwork of fields etc. for which the permeability score of each landscape feature is known - the least-cost-paths will need to choose any possible route through the fields, not follow roads or similar.
(I am using QGIS-2.14.1-Essen with GRASS).