MASK and r.cost?

GRASS GRASS user
1

I have a student here that have been doing his Msc thesis project about
finding optimal gravel pits for different building sites. He has been
using r.cost to compute cost for different locations.

If he only wants to travel along roads it would be nice if we could
use the MASK to filter out surrounding fields and forest. But it seems
like r.cost is ignoring the MASK. We had to solve it by setting very
high cost values for the areas beside the roads.

Is there some reason why the MASK is not considered in r.cost ?
Couldn't the calculation be speeded up if you could mask pixels ?
Is there something that I have overseen here ? I haven't used
r.cost so much myself.

Lars

Lars Schylberg Email: larss@fmi.kth.se
Dept. of Geodesy and Photogrammetry
Royal Institute of Technology (KTH) Tel. +46 8 790 86 33
S-100 44 STOCKHOLM, SWEDEN Fax. +46 8 790 66 10

2

LARS, there was a digital report from GRASS conference about road planning
and evaluation using r.cost layer. If I remember right R. LOZAR was the
author describing this project using GRASS-3.0, but the GRASS'prgrs
should know it better me.

FH-sax-de