On Thu, 2009-09-10 at 17:48 -0400, James McManus wrote: > Hi - I'm having an unusual problem with some maps I produced with > Mapnik. With some choropleth maps I'm getting incorrect output. This > can best be seen by comparing maps I've produced using Mapnik: > http://www.piedmontgeographic.com/wakesearch.html and Mapserver: > http://www.piedmontgeographic.com/example1.html > > If you look at the center of the map, you will see a tract (tractid > 051600) that has a different color value between the Mapnik and > Mapserver produced images. If you activate the searcher and select > this tract you will see that the avg_r_tax_val_0906 is 670473.65, wich > means the Mapserver image is correct. How is the happening? I've > examined the mapfile many times, and it is correct. Most of the > tracts are correct. Only a few come out incorrect!
It would be worth checking that the polygons describing the missing tracts are valid geometries, e.g. => select isvalid(the_geom) from table_name where tract_id=... You should also verify that they are defined in a clockwise direction, the ST_ForceRHR()[1] function should be able to do this for you. If those do not help then you may need to narrow down the data to see if there is anything else which looks odd about those missing polygons. Jon 1: http://postgis.refractions.net/docs/ST_ForceRHR.html _______________________________________________ Mapnik-users mailing list [email protected] https://lists.berlios.de/mailman/listinfo/mapnik-users
