I use QGIS 3.16. For a wildlife conectivity model I used the plugin Least-Cost Path. For robustness of paths I used 3 different cost rasters for the same start and end points. I want to know which paths are calculated in all three cost rasters (very robust), which just in 2 cost raster(medium robustness) and which just in 1 (not robust). How do I achieve this? Idea: give value 1 to each path, merge the 3 layers and sum up the values so that the path shown in each cost raster gets value 3.

But which tool to take? Or is there a better idea?

  • What does your path output look like, raster or vector data? Which values/attributes? Aug 19, 2021 at 6:28
  • The actual output of least cost path analysis is a multilinestring vector with values of costs per path between each start and endpoint. i converted the vector into a raster where all paths have value one and the rest no data. i thought to go along the with raster instead of vector, but maybe it is better to use vector and assign different values (1 for path, 0 for no path)?
    – Flynx
    Aug 19, 2021 at 8:52
  • Another idea: what would be the command in Field calculator for the sum of the values? I did vectzorize the raster, resulting in a vector with value 1 for path and then aggregated it. The attribute table shows values of each path but not the sum of the segments where they overlap. I guess i could achieve this in Field calculator?
    – Flynx
    Aug 19, 2021 at 10:00
  • I found one possible solution, but probably time consuming: I used raster calculator to sum the three raster layer, this gives me the patches where all three paths overlap as far as I understand it. I again used raster calculator for summing up just two layer for the robust paths 8did that 2 times for the rest of combination)
    – Flynx
    Aug 19, 2021 at 10:57


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