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I need to perform a cost-distance analysis and cost allocation analysis for a tsunami evacuation model. As only open and free available data is used, it would be also good to use open source software only.

Since Grass GIS and SAGA tools do not seem to cover a cost allocation analysis, I tried Whitebox GAT (GIS Analysis --> Cost-distance-analyses).

Until now I had no success. I created a small (4x4 pixel) raster to test the tool but when I click "Run" (for the cost-accumulation) I get no result (Whitebox GAT then covers 90% of the CPU usage and seems to calculate (800mb RAM-usage), but after 15minutes I cancelled the process. I have 4gb of RAM and 4x2,1 GHz cpu).

Does anybody used Whitebox's tool for cost-distance analyses and had success? Maybe I just don't get how the input data should be arranged, please see the attached picture - am I right? (Source cell -> all positive values)

Maybe someone knows an alternative to Whitebox.

cost_distance

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Least-cost pathway analysis can be a bit tricky for sure. I've written a short tutorial (http://jblindsay.github.io/WhiteboxTutorials/LCPAnalysis/lcpa.html#/themes) that will walk you through the process of generating one in Whitebox GAT. The answer format of the GIS.SE isn't particularly conducive to the lengthy and detailed answer that is necessary to address your issue so hopefully this is better. One thing to consider in the process is that the cost-accumulation step uses the SPREAD function, which depending on the raster size and the complexity of the cost surface can require many iterations and can be quite a lengthy process.

EDIT: I found it hard to believe that other GIS wouldn't implement a LCP analysis, given how frequently this problem arises, and I found that GRASS has the r.cost tool and SAGA has the Least Cost Paths module. My guess would be that most GIS with raster capabilities offer similar functions but their naming may be somewhat different.

  • Thank you for the nice tutorial - it is very helpful. Concerning the GrassGIS tool r.cost: Until now I had only started the tool through the QGIS interface. Using it directly from GrassGIS, it provides more options including the needed cost allocation and backlink output parameter. Problem solved! – Hannes Bl Sep 14 '15 at 16:34

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