[mapserver-users] accessing different band values in the same layer

[Helen San Segundo Navazo]

ok, thanks Mike.
A solution could be to transform the raster in a shape file, and to put 
the different band values in different attributes of each element, and 
then use the attributes values for selecting symbol and angle.
Thanks,
Helen

El 14/06/12 15:03, Smith, Michael ERDC-RDE-CRREL-NH escribió:
> Helen,
>
> It does not appear that you can. Based on the docs
>
> Raster classifications always take place on only one raster band. It
> defaults to the first band in the referenced file, but this can be altered
> with the BANDS PROCESSING directive. In particular this means that
> including even a single CLASS declaration in a raster layer will result in
> the raster layer being rendered using the one band classification rules
> instead of other rules that might have applied (such as 3 band RGB
> rendering).
>
> http://mapserver.org/input/raster.html
>
>
>
> You could have multiple layers and do classification on each band by
> changing the first value in the PROCESSING BANDS directive.
>
> Mike
>
>
> On 6/14/12  8:27 AM, "Helen San Segundo Navazo"<hsansegundo at meteo.cat>
> wrote:
>
>> Hi,
>> I have a raster file with different bands inside it.
>> when I create my mapfile inside the layer tag I can define the bands I
>> want to access with  PROCESSING "BANDS=4,2,1"
>> When I select 1 band I can access to its data using the EXPRESSION tag:
>>      CLASS
>>          NAME "0 - 5"
>>          EXPRESSION ([pixel]>= 0 AND [pixel]<  5)
>>          STYLE
>>          COLOR 80 0 0
>>          END
>>      END
>> But if I select more than one band, how can I do to acces to the
>> different band values inside the same EXPRESSION tag? is it possible?
>>
>> The problem is that I have wind information in different bands, in one
>> band I have speed and in other band I have direction, and I have to draw
>> the wind symbol depending on both values.
>> Is possible to acces to the different pixel band values inside the same
>> EXPRESSION tag?
>> Thanks,
>> Helen
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>