Upgrade to SpatiaLite 5

[bricelam]

See the docs. It looks like there's a bit of chaos around PROJ.6 on Windows. We may also need to upgrade existing databases and start calling a new function to initialize the metadata tables. We can also take this time to move some of the SpatiaLite functionality out of the SQLite provider and into the NTS extension. We can also reconsider how we redistribute SpatiaLite on Windows.

[bricelam]

This is currently blocked (SpatiaLite is at version 5.0.1 at the time of writing).

In addition to PROJ 6 depending directly on SQLite, the KNN feature, and even parts of the base SpatiaLite code also depend directly on SQLite. This means that mod_spatialite is not a generic SQLite extension, but rather it must be compiled against the same SQLite library that it will eventually be loaded into. While this works just fine with the system version of SQLite, it falls down with SQLitePCLRaw's bring-your-own native library model.

[bricelam]

mod_spatialite has been updated, and they’ve asked for teams to verify that it can work now.

https://www.gaia-gis.it/fossil/libspatialite/wiki?name=June+2021+update&p

[bricelam]

Success! It looks like we're unblocked as soon as they release a new version. I've reported back on their mailing list.

[ajcvickers]

@bricelam Not doing for 6.0?

[bricelam]

Not planned. I don’t think they intend to release for a while. It also requires a bit of design on our side to ensure a smooth upgrade (e.g. with migrations) from v4. It was in the 6.0 milestone to ensure timely validation on our part.

[ajcvickers]

Note: see test issue in #27662. If we don't add support in 7.0, then consider adding a check and throwing a nice exception. Also consider adding a check in the tests to skip these tests if 5.0 is installed.

[clahil-linum]

Supporting the nativ GeoPackage format (like described here: https://www.geopackage.org/spec121/index.html#gpb_format) would be nice too. In theory one could use "SELECT AutoGPKGStart()" but in my experience working with the prefixed "vgpkg_*" tables is unrealiable. GeoPackage is avaiable nativ within Qgis.

For more information about the virtual vgpkg topic visit: https://www.gaia-gis.it/fossil/libspatialite/wiki?name=Virtual+Tables+(misc) (scroll down to VirtualGPKG)