[mapserver-users] How to display a raster with RGB bands and querying additional bands in MapServer 6?

[Paolo Corti]

Hi all

I have a raster with 4 bands: first 3 bands are for RGB value, the 4th
band is the actual value of the variable.
In the viewer I want to display the raster using the RGB values, and
query the 4th band.

This is the layer definition in my mapfile:

    # test
    LAYER
        NAME "test"
        TYPE RASTER
        DATA "../gtiff/production/20111001.vrt"
        STATUS ON
        TEMPLATE     "templates/variable_template.html"
    END

This was working correctly in MapServer 5.6: the raster layer was
correctly displayed using the first 3 bands (RGB), and I could
succesfully query the 4th band in templates using [value_3].

But after migrating to MapServer 6, the layer is rendered using all of
the 4 bands (the 4th being the alpha channel, I guess).
If I use the PROCESSING directive, set to "BANDS=1,2,3", then the
raster is correctly displayed but the 4th band can't be queried.

Is there a way to get this working in MapServer 6 with just one layer
definition, or do I need an additional layer just for querying?

thanks in advance
p

-- 
Paolo Corti
Geospatial software developer
web: http://www.paolocorti.net
twitter: @capooti
skype: capooti