mapnik/tests/visual_tests/styles/marker-interior-position.xml

<Map
    background-color="#eee"
    srs="+proj=longlat +ellps=WGS84 +datum=WGS84 +no_defs">
    <Parameters>
        <Parameter name="sizes">600,400</Parameter>
    </Parameters>

    <Style name="poly">
        <Rule>
            <PolygonSymbolizer />
            <MarkersSymbolizer stroke-width="0" width="7" placement="interior" fill="blue" allow-overlap="true"/>
            <MarkersSymbolizer stroke-width="0" width="7" placement="point" fill="red" allow-overlap="true"/>
            <DebugSymbolizer />
        </Rule>
    </Style>

    <Layer name="bug" srs="+proj=longlat +ellps=WGS84 +datum=WGS84 +no_defs">
        <StyleName>poly</StyleName>
        <Datasource>
            <Parameter name="type">csv</Parameter>
            <Parameter name="extent">-1 -1 11 11</Parameter>
            <Parameter name="inline">
                id|name|wkt
                1|Example|Polygon((0 10, 0 0, 1 0, 1 7, 6 7, 6 0, 10 0, 10 10, 0 10))
            </Parameter>
        </Datasource>
    </Layer>
</Map>