How to read geometry from gpkg?

Question

I have a gpkg file. I trying to open it with spatial_lite gui and cast geometry to GML.

select AsGML(geom) from MyTable

but i got null. I tried another functions AsText(), AsWKT(), st_asText()... but anyway i got null. BTW function ST_GeometryType(geom) returns LINESTRING, but other functions don't work.
My final goal is to cast geometry from gpkg to GML on c#. But it's looks impossible because I cannot even select geometry in spatial_lite gui.
Do I use wrong queries? What can be wrong here?

Answer 1

The binary format for geometry in GeoPackages is not compatible with the format used in Spatialite. That's (partly) why GDAL has separate drivers.

When I start the Spatialite GUI it helpfully displays this:

And that means instead of querying the table d I can query vgpkg_d and the Spatialite geometry functions will work:

If I query from the original table I get NULL, like you.

If your spatialite GUI doesn't show that message or create the virtual tables then you need to upgrade or install some other components.