[postgis-users] line simplication
dblasby at refractions.net
Thu Feb 27 09:33:33 PST 2003
>I'd like to receive feedback about some issues:
> 1: Some polygon rings reduce to a single point or line (2 or 3 points).
> 2: Some lines reduce to a single point (1 point).
> 3: Points are untouched.
> When encountering these cases what should the function do ?
I think the primary goal should be to produce valid geometries:
1. remove rings that are are 2 or 3 points. If its the outer ring,
remove the entire polygon
2. remove lines that are only one point. Alternatively, you could
return a POINT (but the type change will be problematic), or a line with
the first and last points being the same.
As an aside, if you're simplifying polygons, you're probably running the
risk of producing non-valid ones. You could be introducing
self-intersection problems or having your holes outside the polygon.
I cannot wait to get this in the main code base!
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