[QGIS-Developer] QGIS WCS is requesting FULL dataset?

Nyall Dawson nyall.dawson at gmail.com
Sun Oct 14 16:54:17 PDT 2018

On Fri, 12 Oct 2018 at 20:48, Richard Duivenvoorde <rdmailings at duif.net> wrote:
> which is the whole of the Netherlands (in a 10x10 pixel output??) and
> after that a more proper bbox.

I can't explain the background here, but it seems deliberate. There's
a comment before this request is made:

  // It may happen (GeoServer) that extent reported in
spatialDomain.Envelope is larger
  // than the coverage. Then if that larger BBOX is requested, the
server returns
  // request BBOX intersected with coverage box scaled to requested
  // GDAL WCS client does not suffer from this probably because it
probably takes
  // extent from lonLatEnvelope (it probably does not calculate it from
  // spatialDomain.RectifiedGrid because calculated value is slightly

  // To get the true extent (it can also be smaller than real if
reported Envelope is
  // than real smaller, but smaller is safer because data cannot be
shifted) we make
  // request of the whole extent cut the extent from spatialDomain.Envelope if
  // necessary"

 getCache( 1, mCoverageExtent, 10, 10 );

Radim may know more and may be able to explain if this workaround is
still necessary


> Is this supposed to go like this?
> I reckon that (if the WCS data does not have overviews), loading the
> whole dataset all the time is pretty intensive.
> Anybody more familiar with this can tell something about this?
> Regards,
> Richard Duivenvoorde
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