Thanks again Even and Fernando, you've both provided a lot of helpful information that has turned this into a very instructive Linux learning opportunity.
Even: can I confirm that, in the third option you suggested (the "less ugly alternative"), this would involve: 1. Installing QGIS using Software Manager (or any other way, just not necessarily building it from source) 2. Building a second instance of GDAL from source which has the same version as whatevever GDAL version is created by the QGIS installation (ex.: 3.8.4) and which is built with the Mr Sid driver. 3. This second instance of GDAL is given its own secluded /opt/gdal_3_8_4 folder to keep it separate from /usr 4. Setting GDAL_DRIVER_PATH will make GDAL search /opt/gdal_3_8_4/lib/gdalplugins for additional plugins, such as the MrSid driver. This should affect any instance of GDAL, whether I'm running it through QGIS or through the command line? Did I get all that correct? On Sat, Sep 28, 2024 at 10:33 AM Even Rouault <even.roua...@spatialys.com> wrote: > Andrew, > > $ ldd /bin/qgis.bin | grep gdal > > libgdal.so.34 => /lib/x86_64-linux-gnu/libgdal.so.34 (0x00007a0581a00000) > > But I'm not sure what to do with that information. > > /lib/x86_64-linux-gnu/libgdal.so.34 is the version of GDAL that comes with > package manager, so 3.8.4 here > > I'm not sure how you are familiar with the dynamic linking concepts and > tools, but if you're not, reading > https://opensource.com/article/22/5/dynamic-linking-modular-libraries-linux > or related resources on dynamic linking might help you understand why those > seemlingly "weird" behaviors are totally explainable. Takes time, and even > with experience, mixing up several versions of a library on a system and > being confused is not uncommon > > I'm going to hate myself for the below suggestion, and you probably too > when it will hit you back in the face (so forget I've told you about it > ;-), ... but ... to quickly workaround your issue, you can do: > > sudo ln -s /usr/lib/libgdal.so.35 /usr/lib/libgdal.so.34 # i'm > already hating myself > > sudo mv /lib/x86_64-linux-gnu/libgdal.so.34 > /lib/x86_64-linux-gnu/libgdal.so.34.disabled # I'm hating myself even > more... > > And now launch QGIS.... As GDAL keeps a backwards compatible C ABI, this > ugly substitution of the expected GDAL 3.8.4 version at build time is > supposed to (mostly) work. That said, you might run in occasional bugs, > where QGIS tries to workaround GDAL specific bug, based on the version of > GDAL QGIS was built against... > > OK, I believe you've been sufficienly warned this is *not* the normal way > of proceeding, just a quick&dirty workaround > > To undo the above mess: > > sudo mv /lib/x86_64-linux-gnu/libgdal.so.34.disabled > /lib/x86_64-linux-gnu/libgdal.so.34 > > sudo mv /usr/lib/libgdal.so.34 /usr/lib/libgdal.so.34.disabled (i'm > always nervous doing a rm in /usr territory, so I tend to just rename ...) > > The clean solution would be that you rebuild QGIS against your installed > GDAL, but that would be for another episode. Another friendly advice would > be that when doing a custom build you don't do CMAKE_INSTALL_PREFIX=/opt , > but here something like CMAKE_INSTALL_PREFIX=/opt/gdal_3_10_master to avoid > messing with /usr which should be only the territory of your package > manager tool. > > > Another less ugly alternative would be that you download > http://download.osgeo.org/gdal/3.8.4/gdal-3.8.4.tar.gz, build it with > support of the MrSID driver as a plugin, with > -DGDAL_ENABLE_DRIVER_MRSID_PLUGIN=ON, install it in /opt/gdal_3_8_4, and > then just set the GDAL_DRIVER_PATH=/opt/gdal_3_8_4/lib/gdalplugins > environment variable. That way you would use the system GDAL library with > just the addition of the MrSID driver. > > Actually that might not be terribly harder to do than my above hacks, so > I'm definitely encouraging you to explore that way > > And ... you should know that the company behind the MrSID SDK has declared > they won't ever release any new binary version of it. This means that at > most in a few years, this SDK will likely be totally unusable on modern > systems. So everyone using SID files had better convert them to something > else, like COG, when they still have a chance... > > /me taking a passport to an undisclosed country without extradition > agreement. > Even > > -- http://www.spatialys.com > My software is free, but my time generally not. > >
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