# Tag Info

6

Because you are using the ee.Image.and() method in your cost calculation, the resulting cost variable is binary. That is why the results seem non-sensical. The units of the output of ee.Image.cumulativeCost() are the cost input parameter's unit multiplied by a unit of meter. You can test this by examining the result of a unit cost input (script link). So to ...

4

The formulae in wikipedia and the R doc are identical, lets see what they say walking speed is on flat ground: > tobr = function(m){6 * exp(-3.5*abs(m+0.05))} > tobr(0) [1] 5.036742 About 5 units. Is that km/h or m/s? If it was 5 m/s that would be 5 * 3600/1000 = 18 km/h. That's a pretty quick running pace, never mind walking. So I think gdistance ...

4

The results of these functions are not trivial to mentally visualise as they are based on transition matrices, but consider this toy e.g.: N.B. i'm using a projected coordinate system, British National Grid, to simplify things a bit as geoCorrection will begin to take into account north/south & east/west distortions of latlong rasters by using great ...

2

Any luck coming up with reasonable results for this yet? I've also been hammering away at this process a bit to map wet areas using some additional information gleaned from this paper (available open source and on researchgate): White, B., Ogilvie, J., Campbell, D. M., Hiltz, D., Gauthier, B., Chisholm, H. K. H., ... & Arp, P. A. (2012). Using the ...

1

I found two possible workarounds: Update to QGIS 3.4.1. For QGIS 2.18: In the r.walk.points tool, use "GRASS GIS 7 region extent" to manually select an area that is smaller than the input slope raster. However, I'll leave this question open in case someone finds a real answer.

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