What Mapnik and postgis versions are you running? Also, how are you rendering tiles? While the PostGIS St_extent does take longer than St_estimated_extent it should only need to be called once by Mapnik and in that sense is just a startup cost and not a rendering issue.
Dane --- \o/ --- Sent from my phone On Dec 22, 2009, at 7:20 AM, spillocaster <[email protected]> wrote: > > Hi all, > > I have a huge problem with rendering maps with mapnik. In some > regions, > mainly at the border of the data extent, some data is not fully > rendered. > For example, the forest is rendered properly, but when I go to the > border of > the country which is also the border of the data extent, the forest > disappears. > This happens also with other layers like built-up areas and streets. > Here is > an example layer from my XML: > > ... > <Layer name="forest" status="on" srs="+proj=latlong +datum=WGS84"> > <StyleName>forest</StyleName> > <Datasource> > <Parameter name="type">postgis</Parameter> > <Parameter name="host">localhost</Parameter> > <Parameter name="dbname">default</Parameter> > <Parameter name="user">user</Parameter> > <Parameter name="password">user</Parameter> > <Parameter name="table">(select the_geom,class from polygons) as > forest</Parameter> > <Parameter name="estimate_extent">true</Parameter> > </Datasource> > </Layer> > ... > > This is a general problem, but I think only with huge tables. Here > are some > of my tables: > > Table "polygons": > mapping=# SELECT count(*) from polygons; > count > --------- > 6485787 > (1 row) > > Table with streets: > mapping=# SELECT count(*) from streets; > count > --------- > 6386694 > (1 row) > > Table with paths: > mapping=# SELECT count(*) from paths; > count > --------- > 9684396 > (1 row) > > The only solution to get a correct map ist to set the parameter > ="estimate_extent" to false, but then the whole table will be > scanned and > the rendering time is much too long. I also tried to reduce the > extent of > the layer for rendering smaller areas: > > <Parameter name="estimate_extent">false</Parameter> > <Parameter name="extent">9.2,47.0,13.7,48.8</Parameter> > > But when I want to render the whole country, then this is no > solution. See > also my examples with activated and deactivated estimate_extent > parameter: > http://old.nabble.com/file/p26889083/map_estimate_true.png > map_estimate_true.png > http://old.nabble.com/file/p26889083/map_estimate_false.png > map_estimate_false.png > > Does anyone know, where the problem is and how to solve this? > > cheers > Jürgen > > -- > View this message in context: > http://old.nabble.com/Problems-with-%22estimate-extent%22-tp26889083p26889083.html > Sent from the Mapnik - Users mailing list archive at Nabble.com. > > _______________________________________________ > Mapnik-users mailing list > [email protected] > https://lists.berlios.de/mailman/listinfo/mapnik-users _______________________________________________ Mapnik-users mailing list [email protected] https://lists.berlios.de/mailman/listinfo/mapnik-users
