[OSM-talk] wetland type rendering rules in mapnik xml?

[Ulf Mehlig]

Hello,

I'm currently experimenting to render a map via mapnik from OSM data in
a postgresql database, +- as described in

        http://wiki.openstreetmap.org/wiki/Mapnik_Example

However, I've come to a dead end trying to render different types of
wetland areas tagged according to 

        http://wiki.openstreetmap.org/wiki/Tag:natural%3Dwetland

with different colours/patterns via (naive) rules like

<Style name="leisure">
   [...]
    <Rule>
      <MaxScaleDenominator>100000</MaxScaleDenominator>
      <Filter>[natural] = 'wetland' and [wetland] = 'mangrove'</Filter>
      <PolygonPatternSymbolizer file= "./mangrove.png" type="png" width="80" height="80"/>
    </Rule>
    <Rule>
      <MaxScaleDenominator>100000</MaxScaleDenominator>
      <Filter>[natural] = 'wetland' and [wetland] = 'marsh'</Filter>
      <PolygonSymbolizer>
        <CssParameter name="fill">#d6e799</CssParameter>
     </PolygonSymbolizer>
    </Rule>
   [...]

Am I right in presuming that rules like this cannot be used without
changing the database structure? Are there any possibilities to achieve
mapnik rendering of different wetland types given the current tagging
scheme?

Many thanks for your help!
Ulf

-- 
 Ulf Mehlig <ulf.mehlig at gmx.net>
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