[GRASS5] Polygon Simplification... (d.area revisited)
Eric G. Miller
egm2 at jps.net
Tue Dec 11 11:30:46 EST 2001
On Tue, 11 Dec 2001 15:48:18 +0000, Glynn Clements <glynn.clements at virgin.net> wrote:
> Alex Shevlakov wrote:
> > I guess this is to enable functions like R_polygon_abs
> > to handle islands?
> R_polygon_abs wouldn't be the right place for it. However, it would
> allow d.area to tesellate the shape into a set of convex polygons,
> each of which would be passed to R_polygon_abs.
To clarify, the method I'm trying to implement would not guarantee
convex polygons as a result, only simple polygons.
> Also, doesn't v.report need something like this for area computations?
I wouldn't think this is necessary for area computations. For area you
can calculate the exterior and any interiors and then subtract the
interiors from the exterior. Haven't done it myself, but I'm pretty
sure this is already a capability available in GRASS. There are some
tricky methods for the computation that do summation of parts with
positive/negative areas to get the correct area of a simple polygon.
Eric G. Miller <egm2 at jps.net>
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