A question regarding the function ST_Simplify:I have a postgis layer of watershed polygons that I would like to simplify, yet while keeping all shared edges. In other words, I'd like to remove vertices along shared boundaries without creating gaps between adjacent polygons. I'm no expert in how the Douglas-Peuker algorithm works, but I found this past postgis-users thread:
[postgis-users] Simplify() and direction dependencyhttp://postgis.refractions.net/pipermail/postgis-users/2005-January/ 006590.html
It seems that directionality of the lines making up the multigeometry may cause gaps or slivers between polygons in cases. Whether or not this is the correct explanation, it IS what am experiencing. Perhaps this could be avoided by fixing the input data, but short of modifying the directionality of my data, are there any other functions or ideas regarding the ST_simplify command that might be helpful here?
Details: Postgis 1.3.1 build on Mac Os 10.4 with postgresql 8.2.5 using multipolygon data imported from shapefile.
A graphic to illustrate the slivers is attached: dark black line is raw dataset, blue polygons on top are simplified using 5000 as tolerance.
Thanks, Dane
Picture 35.png
Description: application/applefile
<<inline: Picture 35.png>>
_______________________________________________ postgis-users mailing list postgis-users@postgis.refractions.net http://postgis.refractions.net/mailman/listinfo/postgis-users
