[OSGeo-Discuss] WCS/WMS accuracy tests?

Frank Warmerdam warmerdam at pobox.com
Wed Dec 9 06:44:26 PST 2009

Steven M. Ottens wrote:
> Mapserver doesn’t offset the data unless it is physically impossible
> (non-native, non-multiple resolutions, extents which don’t snap to source
> data) but produces a multi-band geotiff where the source data is single
> band.


Thanks for the excellent post.  I'd be interested in following up on the
singleband / multiband issue with MapServer WCS when you have time.  I
vaguely recall there being an issue with this at one point but I thought it
was solved quite a while ago.  So if it persists in 5.6.0 I'd love a chance
to fix it.

Andrea Aime wrote:
 > Steven M. Ottens wrote:
 >> Hi all,
 >> I've finished my tests. The conclusion: Geoserver has a bug which
 >> offsets all the results by half a pixel, this is a known issue with
 >> the definition of the location of a pixel. Added to this there’s the
 >> no-data border which appears with non-native, non-multiple requests.
 >> I presume that will be gone once the pixel issue is resolved.
 > Ah hem, are you sure it's correct to call it a bug?
 > My impression is that we are respecting the OGC specs to the letter and
 > that, as it often happens, the real world is actually working
 > differently, but I need to double check with Simone that dealt with
 > this issue more in detail

Andrea / Simone,

I have set myself to watch GEOS-3702.  I'd like to be sure we all reach
the same understanding of the specification.

Best regards,
I set the clouds in motion - turn up   | Frank Warmerdam, warmerdam at pobox.com
light and sound - activate the windows | http://pobox.com/~warmerdam
and watch the world go round - Rush    | Geospatial Programmer for Rent

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