I want to calculate a cost distance model between a source of raw material and a group of sites. Raster and vector data are in the same CRS (EPSG 32615). I was able to use r.walk and get my cost and direction rasters. Whenever I want to use r.drain, I get:

Converting outputs Loading resulting layers The following layers were not correctly generated. Least cost path You can check the log messages to find more information about the execution of the algorithm

This is the log:

GRASS GIS 7 execution commands g.proj -c proj4="+proj=utm +zone=15 +datum=WGS84 +units=m +no_defs" r.external input="C:/Users/gejst/Desktop/COst/rwalk/rwalk.tif" band=1 output=tmp1544491016043 --overwrite -o r.external input="C:/Users/gejst/Desktop/COst/rwalk/dir.tif" band=1 output=tmp1544491016044 --overwrite -o g.region n=2103521.41379 s=1879836.37719 e=394754.028731 w=180548.446796 res=30.0935068748 r.drain input="tmp1544491016043" direction="tmp1544491016044" start_coordinates=312000,1961000 output="outputef66d40f601f408cba4515b177ffa77b" drain="drainef66d40f601f408cba4515b177ffa77b" --overwrite g.region raster=outputef66d40f601f408cba4515b177ffa77b r.out.gdal --overwrite -c createopt="TFW=YES,COMPRESS=LZW" input=outputef66d40f601f408cba4515b177ffa77b output="C:\Users\gejst\AppData\Local\Temp\processing111bde5bc84d4563a5b91f7eeea042c8\de27ee9605134eaf96c3b82d9c8de29f\output.tif" v.out.ogr -s -e input=drainef66d40f601f408cba4515b177ffa77b type=auto output="C:\Users\gejst\AppData\Local\Temp\processing111bde5bc84d4563a5b91f7eeea042c8\2d50226dc6254d79b65c557fce716a27" format=ESRI_Shapefile output_layer=drain --overwrite

I am aware of these questions:

No output generated with "r.drain" GRASS module

How to get r.drain to run in QGIS/GRASS?

and I think I have not make mistakes in the coordinates of the points (brackets, 0s)

In short I do not know what I am missing.I tried to run r.drain in Qgis 2.18.26 (stand allone install), 3.4 (osgeo4w install) running in win10 64.

Any hint is welcome

  • The log looks good to me, too. Really strange.... By any remote chance, (1) the cost raster may not have enough contrast (difference between neighboring cell values) so r.drain cannot find out appropriate route, or (2) the start_point is located at NoData cell or in a pit......??? (just thinking out loud) – Kazuhito Dec 11 '18 at 14:11
  • 1
    First thanks. The region I am working is the south gulf coast of Mexico. It encommpases some some volcanic features as well as sedimentary and alluvial deposits. The dem has variations in height from 0 to 1800 masl. My points are located either in the flood plain or relatively near the coast (archaeological sites) and the origin is a volcano. I do have no data values, but they area at the sea. – Gerardo Jimenez Dec 12 '18 at 3:19

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