[GRASS-user] r.walk doubt
Luis Miguel Royo Pérez
luis.miguel.royo at gmail.com
Fri Sep 5 05:26:30 PDT 2014
I have some doubts with the generation of a cost surface with /r.walk/ .
It's assumed that the resulting layer is measured in seconds, but when I
try to convert seconds in days march (6h per day), the resulting layer
has no sense.
This is the workflow I'm following:
*1st.-* I have several vector layers as roads, rivers, bridges, and a
raster layer of elevation.
*2nd.-* Rasterize the vector layers with a field named "weight" (PESO in
spanish) where I have weighted this variables according to if they
facilitate the walking or not. Reclassify is made if it's needed.
*3rd.-* Find Slope (in percent) layer and reclasify as follow:
*4th.-* r.cross with all the rasterized layer. (roads, bridge, river and
*5th.-* I create a new friction layer using this formula proposed by
Pandolf (1977) with /r.mapcalc/ :
*6th.-* With this layer measured in Watts I use /r.walk/ with default
*7th.-* Once obtained this layer measured in seconds I try to convert it
in hours dividing 3600 and then convert these hours in days march
dividing 6 (6 hours per day).
Well, the results are not what I expected, the max data of this layer is
about 8.000... No sense, it should be something like 3 or 4 days, maybe.
*/Here are the files
I'm using to do this workflow./*
I don't know what I'm missing, maybe is the 4th step wrong? Maybe the 5th?
Another point of view would be nice to me. If you need more info, please
ask for it and I will add to the question.
Thank you very much to everyone.
Thanks a lot!
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