[GRASS-user] Defining quadrants

[Hamish]

> > Michael:
> >> Any thoughts on how to relatively easily define
> quadrants in
> >> a circle around a point? I¹d like to ID the area
> between 315-45
> >> degrees (N quadrant), 45-135 degrees (E quadrant),
> 135-225
> >> (S quadrant), and 225-315 (W quadrant). I¹ve come
> up with a couple
> >> of complicated ways and wonder if I¹m missing an
> easier one?
> > 
> > v.mkgrid + a little script math seems like it could be
> pretty simple.
> > 
> > 
> > note r.buffer does use geodetic distance in lat/lon
> but v.buffer doesn't.
> > (so buffers correctly look like pears on the screen)

Michael:
> I think I need 'pie' slices of a raster circle.


add v.buffer + v.overlay into the mix with v.mkgrid angle=?
or raster eqivalent, g.region to make a 2x2 cell region (quadrants) then r.mapcalc + lat/lon-safe r.buffer?


Hamish