[mapserver-users] Average/Bilinear Resampling and Alpha Bands

[Robert Sanson]

Hi Jason
 
That's not unexpected. RESAMPLE=NEAREST preserves the "nodata" vales used in the mask. BILINEAR or AVERAGE combine values from adjoining pixels, so the "nodata" pixels get some other value.
 
regards,

Robert

>>> Jason Beverage <jasonbeverage at gmail.com> 16/03/2010 4:53 a.m. >>>
Hi all,

I have some imagery that is in UTM that contains an alpha band that
masks out areas with no data.  When I use MapServer to reproject it to
epsg:4326, the masked out area looks good if I set RESAMPLE=NEAREST on
the layer.  If I change the RESAMPLE option to BILINEAR or AVERAGE I
get black splotches in the area that is transparent.

Has anyone else seen this behavior?

I'm using MapServer 5.6.1

Thanks,

Jason
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