[GRASS-user] v.generalize for polygons?

[Daniel Bundala]

Hi,

I am not sure that I understand correcly what you are trying to do,
but as far as I remember, the boundaries are generalized as polylines.
That is, if the boundary contains some corners, they might be removed
which might create the holes. Also, "ovesimplified" lines are removed
by default. These are the lines that are shorter than the threshold.
However, there is a flag(-r?) which prevents the module from removing
them.

Daniel

On Wed, Feb 27, 2008 at 2:19 AM, Hamish <hamish_b at yahoo.com> wrote:
> Hi,
>
>  I have a high-res vector area map of regional districts which I wish to generalize. I am having trouble with finding the correct method in v.generalize to use. Currently every thing I try tends to break the area topology and leave only a portion of the now-open boundary.
>
>  i.e. it should preserve nodes, only generalize (remove) non-node vertices.
>  We can assume there is only a single boundary line between areas, so there shouldn't be topological issues. (or at least only in tiny corner cases where the new generalized line overlaps another feature, but that should be easy to fix with v.clean)
>
>  the idea is to simplify the map before running v.extrude to get something like this:
>  http://grass.osgeo.org/grass60/screenshots/images/inc_employ_usa_2002.jpg
>
>  but without the 600,000 extruded faces created from every little twist in the coastline.
>
>
>  Hamish
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