Nyall, The first error which appears is "WARNING: Datum <Unknown_based_on_Airy_1830_ellipsoid> not recognised by GRASS and no parameters found ".I think all subsequent errors stem from this. This error message occurs whether I choose a CRS transformation or not.
Cheers, Dave On Tue, 9 Feb 2021 at 02:05, Nyall Dawson <nyall.daw...@gmail.com> wrote: > On Tue, 9 Feb 2021 at 05:57, Dave Marshall <43carn...@gmail.com> wrote: > > > > Hello, > > > > I use QGIS 3.4 to visualise LIDAR tiles from the UK which use EPSG:27700 > as the CRS. I put height contours on the images using the r.contour feature > in GRASS. This works extremely well. I have tried a couple of times to move > to a more up-to-date version of QGIS but in each case, the version of > r.contour associated with later versions does not work. These later > versions seem to require some sort of co-ordinate transformation on opening > the LIDAR files (I think to EPSG:4326) and I wonder if this is part of the > problem. Running r.contour generates an error message which seems to > suggest it does not recognise or cannot work with the CRS being used (there > is a reference to Airy Spheroid). > > What's the error? > > Nyall > > > > > > > What I would like to do is to be able to use a more up-to-date version > of QGIS but with the same version of GRASS which I get when I use 3.4. This > version would seem to be 7.6.1 rather than 7.8.5. > > > > There is a similar contour feature in QGIS under \Raster\Extraction but > this does not allow the specification of height ranges which is essential > for the work I am doing to avoid the routine from taking a very long time > to run. > > > > Any help or advice would be much appreciated, > > > > Dave Marshall > > _______________________________________________ > > Qgis-user mailing list > > Qgis-user@lists.osgeo.org > > List info: https://lists.osgeo.org/mailman/listinfo/qgis-user > > Unsubscribe: https://lists.osgeo.org/mailman/listinfo/qgis-user >
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