How to change projection for layer?

Question

i use two seperate datasource for my layers:

• sql database for main map data, this is using EPSG:900913
• osm file for some extra features, this data use EPSG:4326 projection

tiles for both layers are created on server side. what i need to do to generate tiles for EPSG:900913 projection from data in EPSG:4326 projection? is it somewhere in tilecache configuration? in definition map or layer in osm file, or somewhere else?

tilecache.cfg

[test]
type=Mapnik
mapfile=/var/www/tc/osm/test.xml
tms_type=google
layers=global

test.xml

<Map background-color="#00000000" srs="+proj=latlong +ellps=WGS84 +datum=WGS84 +no_defs" >
  <Style name="style">
    <Rule>
      <PolygonSymbolizer fill="#ff0000" />
      <LineSymbolizer stroke="#00ff00" stroke-width="100" />
    </Rule>
  </Style>
  <Layer name="global" srs="+proj=latlong +ellps=WGS84 +datum=WGS84 +no_defs" status="on">
  <StyleName>style</StyleName>
  <Datasource>
      <Parameter name="type">osm</Parameter>
      <Parameter name="file">/var/www/tc/osm/test.osm</Parameter>
    </Datasource>
  </Layer>
</Map>

test.osm

<osm version='0.6' upload='true' generator='JOSM'>
  <node id='-186' action='modify' visible='true' lat='50.0' lon='50.0' />
  <node id='-184' action='modify' visible='true' lat='50.0' lon='-50.0' />
  <node id='-182' action='modify' visible='true' lat='-50.0' lon='-50.0' />
  <node id='-180' action='modify' visible='true' lat='-50.0' lon='50.0' />
  <way id='-91' action='modify' visible='true'>
    <nd ref='-186' />
    <nd ref='-184' />
    <nd ref='-182' />
    <nd ref='-180' />
    <nd ref='-186' />
  </way>
</osm>

map.html

...
var   map = new OpenLayers.Map ("map", {
                controls:[
                    new OpenLayers.Control.MousePosition(),                    
              numZoomLevels:zoomLev,
                maxResolution: 156543.0339,
                units: 'm',
                projection: new OpenLayers.Projection("EPSG:900913"),
                maxExtent: new OpenLayers.Bounds(-20037508.34, -20037508.34, 20037508.34, 20037508.34),
                displayProjection: new OpenLayers.Projection("EPSG:4326")
            } );

var test = new OpenLayers.Layer.WMS( "test", "http://localhost/tc/tilecache.cgi?",
    {layers: 'level_1', format: 'image/png'}, { isBaseLayer: false} );
...

Answer 1

you can do it on your tilecache.cfg configuration file to changing tms_type parameter to #tms_type=google... you can get some information here...

tms_type
    Setting this to “google” will cause tiles to switch vertical order (that is, 
    following the Google style x/y pattern).

i hope it helps you...