[mapserver-users] Need help to debug a code

[Jeff McKenna]

On 12-06-09 4:34 AM, gautam wrote:
> hi,
> 
> While using postgis with mapserver ... i am getting black image in place of
> raster image... please help
> 
> 
> 
> ...
> LAYER
> 	NAME coolwktraster
> 	TYPE raster
> 	STATUS DEFAULT
> 	DATA "PG:host=localhost port=5432 dbname='postgis' user='postgres'
> password='*******' schema='public' table='test' "	
> 	PROCESSING "NODATA=0"
> 	PROCESSING "SCALE=AUTO"
> 	PROJECTION
>           "init=epsg:3003"
>         END
>         METADATA
>           "wms_title" "OFC 1:10.000 single"
>           "wms_srs" "EPSG:3003 EPSG:4326"
>         END
> END
> ...
> 
> 
> Error report:
> 
> [Sat Jun 09 01:49:25 2012].727000 CGI Request 1 on process 2096
> [Sat Jun 09 01:49:25 2012].729000 msDrawMap(): rendering using outputformat
> named png (AGG/PNG).
> [Sat Jun 09 01:49:25 2012].729000 msDrawMap(): WMS/WFS set-up and query,
> 0.000s
> [Sat Jun 09 01:49:25 2012].731000 msDrawRasterLayerLow(coolwktraster):
> entering.
> [Sat Jun 09 01:49:26 2012].252000 LoadGDALImage(coolwktraster): NODATA value
> 0 in GDAL
> file or PROCESSING directive largely ignored.  Not yet fully supported for
> unclassified scaled data.  The NODATA value is excluded from auto-scaling
> min/max computation, but will not be transparent.
> [Sat Jun 09 01:49:26 2012].259000 LoadGDALImage(coolwktraster): NODATA value
> 0 in GDAL
> file or PROCESSING directive largely ignored.  Not yet fully supported for
> unclassified scaled data.  The NODATA value is excluded from auto-scaling
> min/max computation, but will not be transparent.
> [Sat Jun 09 01:49:26 2012].265000 LoadGDALImage(coolwktraster): NODATA value
> 0 in GDAL
> file or PROCESSING directive largely ignored.  Not yet fully supported for
> unclassified scaled data.  The NODATA value is excluded from auto-scaling
> min/max computation, but will not be transparent.
> [Sat Jun 09 01:49:26 2012].269000 msDrawMap(): Layer 0 (coolwktraster),
> 0.540s
> [Sat Jun 09 01:49:26 2012].269000 msDrawMap(): Drawing Label Cache, 0.000s
> [Sat Jun 09 01:49:26 2012].269000 msDrawMap() total time: 0.542s
> [Sat Jun 09 01:49:26 2012].424000 msSaveImage(stdout) total time: 0.155s
> [Sat Jun 09 01:49:26 2012].425000 mapserv request processing time (loadmap
> not incl.): 0.698s
> [Sat Jun 09 01:49:26 2012].425000 msFreeMap(): freeing map at 025D1FE8.
> 

Hello,

Some things I might do/check if I was in this same situation:

- when I load the data into Postgres, I would make sure to assign the
projection (if using shp2pgsl then use the -s switch, if using ogr2ogr
then use -s_srs and -a_srs switches)
- I might use Quantum GIS to view that Postgres layer (http://www.qgis.org/)
- then I would use ogrinfo with the -summary switch to connect to that
Postgres layer and check its spatial coordinates
- I would use the extents returned from ogrinfo in my mapfile EXTENT
parameter
- I would remove the NODATA value (and PROCESSING parameters) from the
mapfile layer and then test with the sh2img commandline utility

I hope that helps you or someone else down the line...

-jeff




-- 
Jeff McKenna
MapServer Consulting and Training Services
http://www.gatewaygeomatics.com/