[gdal-dev] GDALWarp Datasets

[James McClain]

Hello,

Okay, all of that is well-taken.  Thank you for your response.

> If you're not interested in the pixel values, using
GDALSuggestedWarpOutput2()
is a better fit.

Yes, my question was worded a bit unclearly: I am essentially interested in
retrieving warped tiles so the pixels are of primary interest.

Thank you,
James McClain



On Fri, Feb 15, 2019 at 4:58 AM Even Rouault <even.rouault at spatialys.com>
wrote:

> On vendredi 15 février 2019 00:06:28 CET James McClain wrote:
> > Hello,
> >
> > If I may, I would like to a few questions regarding how best to use the
> > GDALWarp function (
> >
> https://github.com/OSGeo/gdal/blob/master/gdal/apps/gdalwarp_lib.cpp#L748-L7
> > 70) and the datasets that it creates.
> >
> > In particular, I am experimenting with using such datasets to read warped
> > extents on an on-demand basis and in a thread-safe way.
> >
> > I have found that the VRT output format is lazy with respect to
> computation
> > and allocation which is great for my use case, but it appears not to be
> > thread safe with respect to reading from a single warped dataset from
> > multiple threads.
>
> No single GDALDataset object of any driver should be used simultaneously
> by
> multiple threads (this extends to any GDAL/OGR class instance). If this
> seems
> to work for GTiff, you're just lucky, but that might just fail as well.
> If you need to access a dataset from several threads, each one should have
> its
> own GDALDataset object (so this won't work for the MEM driver)
>
> >
> > On a more meta level, are datasets created by GDALWarp the right approach
> > (if I want to lazy get warped extents in a thread-safe manner) or should
> I
> > look elsewhere?
>
> If you're not interested in the pixel values, using
> GDALSuggestedWarpOutput2()
> is a better fit.
>
> Even
>
> --
> Spatialys - Geospatial professional services
> http://www.spatialys.com
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