Trouble getting GeoTiiff transparent: what to use ? transparent, offset, transparency ?

[Mark Wright]

try removing the offsite and both transparancies from your mapfile. In
your layer add this:

CLASS
	EXPRESSION ([pixel] != 1)
END

This works for me so that the border around topo maps are transparant.
Make sure the background color in your html file equals the color that
you are removing. I don't use arcgis so I don't know if the background
values start with 0 or 1. If they start with 1 then change the
expression above from 1 to 0.




Mark

On 3/25/06, Steven De Vriendt <gisaalter at gmail.com> wrote:
> Hi List,
>
> I have trouble displayin a geotiff. I'm not quite familiar with raster images...
> When viewing the raster in MapServer I get a black image.
> When viewing the raster in ArcGIS I get an image but I have to set
> display background value 1 as no data to make it transparent.
>
> In my mapfile I set following options
> TRANSPARENT ON (for the mapfile)
>
> OFFSITE 0 0 0
> TRANSPARENCY 0
> that's for the raster layer itself.
>
> Can anyone give me advice on how to get the black background which I
> can see now transparent ?
>


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