Generate XYZ tiles (MBTiles): MBTiles 1.1 spec violation

[oarchner]

Created MBTile files are missing the description record in table metadata. According to the MBTiles 1.1 specification, this entry is mandatory.

Steps to reproduce the issue

1. Raster Tools/Generate XYZ Tiles (MBTiles)
2. Enter a valid map extent
3. Define the output as: test.mbtiles
4. Run the tool
5. Open the output with a SQLite DB viewer like dbeaver
6. The description record is missing
   
7. Fix to fulfill the spec: `insert into metadata (name,value) values ('description','test');
   

Versions

3.40.1

Supported QGIS version

• I'm running a supported QGIS version according to the roadmap.

New profile

• I tried with a new QGIS profile

Additional context

MBTile files with a missing description record can't be added as custom maps to DJI Pilot 2

[agiudiceandrea]

@oarchner, while I see that the value of the version key metadata is set to "1.1" by the algorithm itself

QGIS/src/analysis/processing/qgsalgorithmxyztiles.cpp

Line 497 in 0b60e0f

mMbtilesWriter->setMetadataValue( "version", QStringLiteral( "1.1" ) );

I'm not sure it refers to the MBTiles specification version number, since the MBTiles specifications say that such key "refers to a revision of the tileset itself, not of the MBTiles specification".

Since the processing algorithm has been developed in Python in 2019 (#9857) by @marcel-dancak and ported to C++ in 2023 (#54321) by @alexbruy, I guess the algorithm was developed referring to the version 1.3 (2018) of MBTiles specification where the description key is not mandatory. Another clue is the fact that the algorithm sets the minzoom and maxzoom keys which are only defined in 1.3 version.

Anyway it should be simple to make the algorithm also add such key in the metadata in order to be compatible with versions 1.1 and 1.2.