[mapserver-users] MapServer CGI GdalWarp parameter passing

[Frank Warmerdam]

Heiko Schröter wrote:
> Hi,
> 
> i need to pass parameters for Reprojection via mapservers CGI interface to gdalwarp.
> Gdalwarp needs the '-wo SOURCE_EXTRA=x' to do the reprojection properly.
> 
> How can this Parameter beeing passed to gdalwarp ?
> 
> Tried the PROCESSING='-wo SOURCE...' key, but probably got the syntax wrong or this is not the right keyword.

Heiko,

MapServer does not use gdalwarp or it's underlying algorithm.  these
two processing options can influence the MapServer source area selection
but there is no direct analog for SOURCE_EXTRA.  There is some hardcoded
logic to grow the source area by two pixels, but this is sometimes far
from being enough.

**LOAD_FULL_RES_IMAGE=YES/NO**
     This option affects how image data is loaded for the resampler when
     reprojecting or otherwise going through complex resampling (as opposed
     to the fast default image decimation code path).  This forces the source
     image to be loaded at full resolution if turned on (default is NO).  This
     helps work around problems with default image resolution selection in
     when radical warping is being done.  It can result in very slow processing
     if the source image is large.

**LOAD_WHOLE_IMAGE=YES/NO**
    This option affects how image data is loaded for the resampler (as above).
    This option, if turned on, will cause the whole source image to be loaded
    and helps make up for problem identifying the area required, usually due
    to radical image reprojection near a dateline or projection "horizon".
    The default is NO.  Turning this on can dramatically affect rendering
    performance and memory requirements.

Best regards,
-- 
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