I'm looking for a FOSS GIS tool to provide Positive Topographic Openness on 32-bit Ubuntu. (which rules out ArcGIS)

Normally I use SAGA GIS for this, but my Ubuntu setup is a bit messed-up after a recent update, and SAGA is crashing on opening (I think it's down to a clash in GDAL versions, but that's a question for another day!)

Are there any other FOSS tools out there which provide this algorithm? I've looked in GRASS and Whitebox GAT but can't find this algorithm.

I understand Relief Visualization Toolbox offers this, but the Linux version only supports 64 bit, and I'm still on 32 bit..

1 Answer 1


In GRASS GIS 7, there is r.skyview addon for sky-view factor, which is very similar to openness. You can check the implementation details here. Download the addon with g.extension r.skyview.

  • 1
    that works, thank you! I'm using it for relief mapping, and aesthetically it looks very similar. Funnily enough, the same upgrade which broke SAGA gave me access to GRASS 7 :)
    – Steven Kay
    May 9, 2016 at 10:41

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