Geometry Boost List: Re: [geometry] polygons with holes

Subject: Re: [geometry] polygons with holes
From: jeffpoly (jfw1000_at_[hidden])
Date: 2012-01-30 17:39:35

Hello Barend,

Thanks for your help. Unfortunately I do not have the shapefil.h file and I
am new to Boost Geometry, so I am not sure that I if I understand your
answers fully.

>This assumes that: 
>- clockwise rings are outer rings (area is positive) 
>- counterclockwise rings are inner rings (area is negative) 

I do not know rings area before construct, actaully I need to make sure that
CW rings are outer rings with positive area, and CCW rings are inner rings
with negative area. Also I do have open rings, could I use similar
algorithm?

>In the sample (shp_read_object) it assumes one exterior ring, but it (or 
>something similar) will work for a multi-polygon as well. 

Sorry that I can not figure out how to make this happen, could you please a
little more details or examples?

Thanks in advance,
Jeff

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