[QGIS-Developer] QGIS server issue: bounding box issues

[Alessandro Pasotti]

On Thu, May 9, 2019 at 12:08 PM René-Luc Dhont <rldhont at gmail.com> wrote:

> Hi Andreas
>
> Le 09/05/2019 à 11:59, Andreas Neumann a écrit :
> > Hi René-Luc,
> >
> > Thanks for the explanation. Any chance we can "influence" that extent
> > calculation (e.g. adding a user-defined margin to that extent?) - I
> > guess a fully manual override would not be satisfactory as data
> > changes, but adding a user-defined margin to that extent might help
> > for both issues we have.
> >
> > Also, this fact that layer extents are stored in QGIS worries me quite
> > a bit. We live in a GDI where any minute data can be changed by any
> > client (QGIS, ArcGIS, Geomedia, you name it). What if Geomedia adds
> > features outside of the layer extent that is stored in the QGIS
> > project, would that data then be ignored by QGIS server, because it is
> > outside of the extent stored in the project file in QGIS?
>
> Yes, new features outside the extent will be ignored by QGIS Server and
> QGIS Desktop if the user does not recalculate the layer extent.
>
> >
> > Anyway - I would rather have global bounding boxes for all layers
> > (defined globally per project) than some calculated exents stored in a
> > QGIS project file that might be outdated quite easily, because other
> > GIS edit the data meanwhile. I am not worried about bounding boxes
> > being too big, but worried about bounding boxes that hide away
> > existing data.
> >
> > Andreas
> >
>
> We, a customer and I, would like to add the ability to define manually
> the extent for each layer. The extent could be calculated, based on the
> CRS and modified by user.
> Do you think, could it be a solution ?
>

That depends on whether the "<BoundingBox>" tag in the WMS GetCapabilities
reponse is meant to be the layer's extent or the features's extent.

If it's the latter, we should not advertise an extent which is differed
from the extent of the features contained in the layer.


-- 
Alessandro Pasotti
w3:   www.itopen.it
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