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
