[QGIS-Developer] Converting to GeoJson missing Z value

[matteo]

Hi all,

when I convert a layer (gpx, 25D shp, etc) to a geojson I noticed that
the geojson file is missing the Z value.

Even when using the drape algorithm and directly saving the output as
geojson, no z values are there.

Is this a limitation of the driver or are some tricks I should use?

BTW: in the saving dialog the "Include z dimension" is checked even if
not active.

Cheers and thanks

Matteo