Alex, Many thanks for the quick response. That would explain why I see the message to select a different CRS when I load these files into later versions of QGIS but all the work I do generates UK Ordnance Survey grid references so I have to use the 27700 projection or one that will generate the exact same numbers. Perhaps I just have to live with the old version.
Cheers, Dave On Mon, 8 Feb 2021 at 21:36, Alexis R.L. <alroyl...@gmail.com> wrote: > PROj might have changed and your file projection is unsupported anymore. > Transfer your layer to something less specific. > > Alex > > > Le lun. 8 févr. 2021 à 14:57, Dave Marshall <43carn...@gmail.com> a > écrit : > >> 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 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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