[GRASS-user] r.to.vect to selected locations only

Hamish hamish_b at yahoo.com
Tue Jun 24 08:54:52 EDT 2008

> > (r.what or v.what.rast) -> r.reclass -> MASK -> 'g.region zoom='
> > (r.what or v.what.rast) -> r.reclass -> r.grow -> 'g.region rast='

G. Allegri wrote:
> r.reclass would reclass all the areas having the same value
> as the one from r.what, so it's not guaranteed that just the area
> around the specified point is considered. Am I wrong?

that is correct; all of that value in the map.

> Are you sure r.grow is useful? As far as I've unserstood it makes
> a sort of r.buffer+r.patch, based on a buffer radii, not
> inspecting the pixel values...

oops, I meant r.cost.

> Yes r.mapcalc can do the work, but I was tinking to something like
> r.lake... Maybe it's more performant. Ok, proabibly it should be
> written with a C routine not bash.

well bash is nice for prototypes and proof of concept. You can worry about C later if you can't stand the slowness. Usually you can stand it.
I've never used r.lake much, so can't comment on if it could offer a solution.

random idea:
Maybe we could add a "module of the day" feed on the grass webpage with module name and label/description one-liner. I continue to find new modules many years after first using grass.



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