<Map srs="+proj=longlat +ellps=WGS84 +datum=WGS84 +no_defs" background-color="lightsteelblue">
  <Style name="My Style">
    <Rule>
      <PolygonSymbolizer fill="#f2eff9"/><LineSymbolizer stroke="rgb(50%,50%,50%)" stroke-width="0.1"/>
    </Rule>
  </Style>

  <Layer name="world" srs="+proj=merc +a=6378137 +b=6378137 +lat_ts=0.0 +lon_0=0.0 +x_0=0.0 +y_0=0.0 +k=1.0 +units=m +nadgrids=@null +wktext +no_defs +over">
    <StyleName>My Style</StyleName>
    <Datasource>
      <Parameter name="type">shape</Parameter>
      <Parameter name="file">../shp/world_merc.shp</Parameter>
    </Datasource>
  </Layer>
</Map>