[GRASSLIST:306] How to satisfy some constraints

[giglio.antonio at katamail.com]

Hi folks,
starting from some maps* I have, I should be able to find one or more
paths that satisfy the sequent constraints:
- path must be in 500m from a road for every x km;
- path must start from a lake at least y sqkm large;
- path must arrive in at least z villages populated area;
- path must be always going-down;
- path must be the shortest one (or the first 10 paths).

x, y and z are 3 variables not yet decided and can be disregarded, because
I'm interested mostly to how-to-work.

*maps I have are:
- roads map;
- DEM;
- lakes map;
- villages map.

I did something similar, calculating areas that satisfy more simple constrains,
as distances constraints, so I had to do only buffers (r.buffer), and, after
selecting areas (assigning 1 to the proper points and 0 to the others with r.reclass),
to calculate the interesting areas (using r.mapcalc: wanted_map=reclassed_buffered_map_1 *
reclassed_buffered_map_2 * reclassed_buffered_map_3....).
Currently, I'm not able to realize HOW I could do to calculate what I need.
Thank you,
Antonio Giglio.

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