Re: [mapserver-users] Raster

[Frank Warmerdam <warmerdam@pobox.com>]

Miroslav Sodja wrote:
> Hi all,
>
> I have questions about raster data. 
> Layer with raster data has 38 images; images are about 4500 pixel width,
> and 6000 pixel height with 2 colors. I have tile index of those images.
> The problem is that every image has border with no data. And that border
> goes across the data of neighbor image. The image should be transparent.
> There is no problem if I have png file format with transparent
> background and map file look like that
>
> LAYER  #raster 50.000
> 	NAME "IME_50"
> 	TILEINDEX "raster/ko_50.shp"
> 	TILEITEM "PNG_NAME"
> 	TYPE raster
> 	STATUS ON
> 	MAXSCALE 60000
> 	CLASSITEM "[pixel]"
> 	CLASS
> 		EXPRESSION ([pixel] <1 )
> 		COLOR 0 0 0
> 	END
> END
>
> But response of IIS and MapServer in that case is very slow. 
> If I have tiff file format of those images I have white space around
> every image in layer but response of IIS and MapServer is fast. Map file
> is the same except:
>
> 	TILEITEM "TIF_NAME"
>
> I can't cut border with no data because images are deformed and new
> world file would be difficult to calculate.
>
> I have MapServer:
>
> MapServer version 3.5 OUTPUT=GIF OUTPUT=PNG OUTPUT=JPEG OUTPUT=WBMP
> SUPPORTS=PROJ SUPPORTS=TTF SUPPORTS=WMS_SERVER INPUT=EPPL7 INPUT=OGR
> INPUT=GDAL INPUT=SHAPEFILE
Miro,

Don't you just need to use hte OFFSITE parameter in your LAYER description?
For example, the following would indicate that any pixel with the value 0
should be treated as NODATA.  The GDAL support in MapServer honours this,
at least for colormapped images.

  OFFSITE 0

Best regards,

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