Show user-friendly explanation if las/laz files cannot be used on their QGIS install #41927
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for when a URI cannot be opened in a QGIS install, but the URI matches a format which could potentially be opened in a different QGIS install. This can be used to show user-friendly warning messages advising user why a particular uri cannot be opened on their QGIS install. For example, if a QGIS install is built without the PDAL library then las/laz files are unusable, and this method can be used to retrieve a user-friendly warning as to why the las/laz files cannot be used on their QGIS build. Instead of just showing the user a generic "not a valid or recognized data source" error, we can use this api to show more helpful URIs about the specific uri. Initially intended to help advise users why LAS/LAZ files cannot be opened on their QGIS install, but also could be used e.g. by mdal to advise users about missing third party libraries preventing them from opening certain mesh files, etc....
their QGIS install
Show user-friendly explanation if las/laz files cannot be used on their QGIS install
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Thanks a lot Nyall! |
Show user-friendly explanation if las/laz files cannot be used on their QGIS install
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@nyalldawson I realize this has been created with the pdal issue in mind and las/laz files. But can this also be used when providers fail to load files due to their own missing dependencies upstream? I just tried using the new OSGeo4W "testing" installer, and QGIS choked on a number of .tifs in my existing projects. Turns out its gdal 3.2 is complied without internal libtiff and so is missing the LERC (de)compression codec which is present in the old build's gdal 3.1.4. I've opened an OSGeo4W ticket for this specific build issue (https://trac.osgeo.org/osgeo4w/ticket/663) but it's made me realize QGIS' error messages are much less informative in the "Keep unavailable layers" dialog at startup, and when asking for layer properties in the Browser, than when adding a new layer to the layer tree (when it at least passed on the gdal "missing CODEC" error message). Seeing this made me wonder whether this API could be used in such instances too, when it's not the file type per se which is unsupported due to not being compiled in to QGIS itself, but something about a specific file which makes the provider choke? |
Yes, totally! (That's why I kept the API as generic as possible) |
Add API to QgsProviderRegistry to obtain user friendly warning messages
for when a URI cannot be opened in a QGIS install, but the URI
matches a format which could potentially be opened in a different QGIS
install.
This can be used to show user-friendly warning messages advising user why
a particular uri cannot be opened on their QGIS install. For example, if
a QGIS install is built without the PDAL library then las/laz files are
unusable, and this method can be used to retrieve a user-friendly warning
as to why the las/laz files cannot be used on their QGIS build.
Instead of just showing the user a generic "not a valid or recognized data
source" error, we can use this api to show more helpful URIs about the
specific uri.
Initially implemented to help advise users why LAS/LAZ files cannot be
opened on their QGIS install, but also could be used e.g. by mdal
to advise users about missing third party libraries preventing
them from opening certain mesh files, etc.... (cc @PeterPetrik @vcloarec @wonder-sk )