[GIS] How to render PostGIS raster with Mapnik XML

mapnikpostgis-2.0rasterxml

I'm trying to manage raster files from PostGIS, which to be rendered using Mapnik. I used raster2pgsql to load those GeoTIFF images to PostGIS, and I think the loading process turned out OK. The problem is to render from Mapnik XML using the PostGIS datasource: the rasters rendered out blank.. The raster files rendered perfectly with Mapnik XML using GDAL datasource, so I suspect my PostGIS raster configuration is at fault here..
Is there any documentation out there that resembles what I am trying to do?

Below is a snippet of my XML file to be used by Mapnik:

<Datasource>
            <Parameter name="type">postgis</Parameter>
            <Parameter name="user">postgres</Parameter>
            <Parameter name="dbname">gis</Parameter>
            <Parameter name="geometry_field">rast</Parameter>
            <Parameter name="estimate_extent">false</Parameter>
            <Parameter name="table">staging.hillshade</Parameter>
            <Parameter name="extent">101,3,103,4</Parameter>            
</Datasource>

I appreciate any help, thanks!

Best Answer

For those who will stumble on this question like me..

It appears that the plugin has been generated (https://github.com/strk/mapnik/tree/2.3.x-pgraster) and has been merged in official Mapnik Repo.

The branch is 2.3.x (https://github.com/mapnik/mapnik/tree/2.3.x)

Now you can build Mapnik from the branch and use PGRaster plugin to use Raster data from Postgis. The xml configuration could be as follows,

> <Layer name="MS-GIS" status="on" srs="+proj=utm +zone=18 +datum=WGS84
> +units=m +no_defs">
>     <StyleName>raster</StyleName>
>     <Datasource>
>       <Parameter name="type">**pgraster**</Parameter>
>       <Parameter name="table">ms_test</Parameter>
>       <Parameter name="**raster_field**">rast</Parameter>
>       <Parameter name="dbname">gis</Parameter>
>       <Parameter name="estimate_extent">false</Parameter>
>       <Parameter name="extent">-20037508,-19929239,20037508,19929239</Parameter>
>     </Datasource> </Layer>
Related Question