[QGIS-Developer] QGIS 3D: Fails with large DTM image

[C Hamilton]

Martin,

Thanks. That is the issue. I'm sure the 3D support is going to continuously
evolve and get better and hopefully sometime in the near future it will
handle no-data values. In the meantime I will use your suggestion of
remapping the no-data values.

Happy holidays,

Calvin

On Sat, Dec 16, 2017 at 12:03 PM, Martin Dobias <wonder.sk at gmail.com> wrote:

> Hi Calvin
>
> I have tested with your layer and the problem is with the no-data
> values - right now the terrain generator does not have a concept of
> no-data values so they are interpreted as valid values, which in this
> case is a very high number (around 1e38) and that breaks the 3D view.
> Best to keep an eye on https://issues.qgis.org/issues/17558 as that is
> essentially the same problem. As a temporary workaround, you could try
> to change your layer's no-data values closer to the valid range (e.g.
> zero or 500).
>
> Cheers
> Martin
>
>
> On Fri, Dec 15, 2017 at 10:51 PM, C Hamilton <adenaculture at gmail.com>
> wrote:
> > The current DEM that I am working with is located here:
> >
> > http://gis3.oit.ohio.gov/ZIPARCHIVES/ELEVATION/
> GRIDMOSAICS/GRE_DEM_MOS.zip
> >
> > I'm surprised that resizing did not help so I am not sure what is wrong.
> I
> > created a small 560x460 image that I have attached. It does not work for
> me.
> >
> > Thanks,
> > Calvin
> >
> > On Fri, Dec 15, 2017 at 4:22 PM, Martin Dobias <wonder.sk at gmail.com>
> wrote:
> >>
> >> Hi Calvin
> >>
> >> Could you please point me to such a DEM to try it out myself? Or even
> >> better, file a ticket on issues.qgis.org so that we do not forget
> >> about it. Not sure from the top of my head what could go wrong there -
> >> the raster size should not be the reason really as the raster data
> >> access is using the same code paths as 2D rendering would. Maybe there
> >> is something in the data that causes the problem. If you resize the
> >> large DEM to e.g. 5000x5000 pixels, does that help?
> >>
> >> Regards
> >> Martin
> >>
> >>
> >> On Fri, Dec 15, 2017 at 8:38 PM, C Hamilton <adenaculture at gmail.com>
> >> wrote:
> >> > QGIS 3D has a lot of potential and works well with small DEM data
> sets,
> >> > but
> >> > when ever I try it with a large DTM image I just get a white screen. I
> >> > tend
> >> > to work with large DEMs (50000 x 50000 pixels and larger) and I would
> >> > love
> >> > for this to work with it properly.
> >> >
> >> > Do you have any ideas why this is the case? I have tried this with an
> >> > AIG/Arc/Info Binary Grid image as well as a GeoTIFF with overviews.
> >> >
> >> > OS: Windows 7; QGIS 3 Version: 2.99.0-238
> >> >
> >> > Thanks,
> >> >
> >> > Calvin
> >> >
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>
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