[GRASS5] Polygon Simplification... (d.area revisited)

[Alex Shevlakov]

Hi,

I have chosen areas with holes and no intersections to
test d.area; it now both outlines and fills the areas
correctly which is due to the major code add-on done
by Eric since release 1.5 to handle isles
(screenpoly.c functions).

Sorry, I can not gather why another algorytm is needed
to handle isles, or that new one is for clipping only?

I'm thinking about cloning part of the new d.area
code into d.what.v.pg to handle drawing and filling
isles correctly.

--alex

--- "Eric G. Miller" <egm2 at jps.net> wrote:
> Okay, haven't finished implementing it yet, but I
> managed to try
> writing up how I'm attempting to do it...
> 
> (bring out the way-back machine about d.area and
> handling
> holes as well as clipping...).
> 
> I think I understand an algorithm that should
> produce the
> desired results.  But I haven't yet finished
> implementing it.
> Given, it might take me a while to get it done, I
> thought I'd
> try to explain it, and if any enterprising soul
> wants to
> give it a crack... just try to get it done before I
> do ;-)
> 
> I've posted a little write-up and some poorly done
> graphics
> that try to illustrate the process at:
> 
>
http://pweb.jps.net/~egm2/grass/algorithms/poly_simplify/algorithm.html
> 
> Perhaps it will make sense to someone?  Perhaps it
> is flawed?
> Perhaps I will figure out how to get working code
> for it...?
> 
> With a little bit more thought, I think the general
> concept
> described can be extended/modified for general
> overlay
> operations...
> 
> -- 
> Eric G. Miller <egm2 at jps.net>
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