[Qgis-user] datum transformation in qgis server

[Jachym Cepicky]

Hi all,

we recently hit a problem, that QGIS server, when serving GeoJSON data
via WFS, is not using correct datum transformation parameters.

1. Original data (EPSG:5514
+towgs84=572.213,85.334,461.94,-4.9732,-1.529,-5.2484,3.5378)
2. QGIS Server GeoJSON over WFS -> automatic translation to WGS84

result is, that the GeoJSON data are shifted about 40m (which is
common problem, if the data are transformed without +towgs84)

In QGIS Server 2.18, there was DEFAULT_DATUM_TRANSFORM environment
variable [1] but this seems to be missing in current QGIS version [2]

How to force QGIS Server 3.x to use datum transformation options?

Thanks

Jáchym

[1] https://docs.qgis.org/2.18/en/docs/user_manual/working_with_ogc/server/config.html#environment-variables
[2] https://docs.qgis.org/testing/en/docs/server_manual/config.html#environment-variables


-- 
Jachym Cepicky
e-mail: jachym.cepicky gmail com
URL: http://les-ejk.cz
GPG: http://les-ejk.cz/pgp/JachymCepicky.pgp