I'm trying to run a least cost path analysis between two points. I've got a shapefile for the origin, and the one for the destination, a slope raster reclassified in to a 10 value scale, and added to weighted overlay. My problem is I'm trying to force the path produced to only cross a river at a ford point. I've created a landuse polygon to attempt this, with most of the river hand digitized, and assigned a name and value, and the a polygon created for the most likely fording spots. I then converted this polygon into a raster and added it to the weighted overlay table mentioned above. My issue is whenever I run the model--no matter how I weight it--it kicks back the above error, saying the number of from cells is zero. When I remove the landuse raster and run the model, it produces a path between the points. I'm assuming then, that I've badly missed up something in the landuse layer, but for the life of me I cannot figure out what it is or how to fix it. I haven't even been able to find a tutorial on the proper way to create a landuse layer. I assumed it was as simple as creating multiple polygons for the different use types and converting that to a raster, but it seems not to be the case. I'm running this whole process in a model built following the instructions here:http://www.youtube.com/watch?v=c3q0DpV8NQo&feature=player_embedded#!. Doe anyone have any idea where I'm going wrong ?
I've now figured out that for some reason, all the raster cells seem to have NoData values assigned to the cells, and reclassifying doesn't seem to be doing anything to change them. How do I assign values to the raster cells ?