Editing same layer with two different geometry columns and type fails

[mathieubossaert]

What is the bug?

I have a layer to draw objects that can be points or polygon. I created 2 different geometry columns in my PostGIS table :

• centroide for points (-> geometry(POINT,2154))
• geometrie for polygons (-> geometry(POLYGON,2154))

Everything's fine in my QGIS project. But once in Lizmap, when I try to save a new POLYGON, it fails and I get an error about geometry type. Lizmap tries to save my polygon into the "centroide" column. As if lizmap was looking into the geometry_columns view and take the first row for the table I edit...

Steps to reproduce the issue

Create a POSTGIS table with two geometry columns, one for points and one for polygon :

CREATE TABLE ponds (
id serial NOT NULL PRIMARY KEY,
name text,
centroide geometry(POINT, 2154),
geometrie geometry(POLYGON,2154)
);

Create a project that calls the same table twice, first time with centroide as the geo column, second time with the geometrie one.

Add try to insert a new polygon

Versions

QGIS 3.22 LIZMAP 3.5.14 QGIS serveur 3.22.16

Check Lizmap plugin

• [ ] I have done the step just before in the Lizmap QGIS desktop plugin before opening this ticket. Otherwise, my ticket is not considered valid and might get closed.

QGIS server version, only if the section above doesn't mention the QGIS Server version

No response

Operating system

? celui de 3Liz

Browsers

Firefox

Browsers version

116.0.2

Relevant log output

No response

[mathieubossaert]

I forgot to mention my actual workaround : I defined 2 views in PostGIS and I use it for Editing. As they are simple views, they can be used as tables and accept insert, update and delete statements..

[nworr]

quick code analysis : the geometry column is guessed (check if field is kind of geometry), https://github.com/3liz/lizmap-web-client/blob/c4fb911add7c571618a88bc2cb6b6b55e1927d98/lizmap/modules/lizmap/classes/qgisVectorLayer.class.php#L397

So when multiple geometry fields in table, the last one will be always be detected as geometry field, maybe we can check the geom type provided by qgis project (is it reliable ?)

[mind84]

I think @nworr is right.

To have two or more geometry column is not frequent, but could be useful in may cases IMHO. The only information about geometry column in the qgs project file is on the datasource xml tag. Take for instance this line in form_edition_snap.qgs test project :

https://github.com/3liz/lizmap-web-client/blob/3a4f56122a3ba7b6084a8144b6cc3fc09418dae8/tests/qgis-projects/tests/form_edition_snap.qgs#L127

The information about geometry column is "stored" as (geom) at the end of the string.

I couldn't find documentation on this.

@Gustry, @mdouchin, @nboisteault do you think that this information is reliable? If so, this information could be stored as a property in the qgisVectorLayer class and could be used to get the correct geometry column.

[Gustry]

@mind84 @nworr They are some unittests about geom column in datasource :

https://github.com/3liz/lizmap-web-client/blob/master/tests/units/edition/qgisVectorLayerDatasourceTest.php#L36

In these tests getDatasourceParameter('geocol') they are a lot of occurences.

Maybe the function is not fully used ?

[mind84]

Maybe the function is not fully used ?

@Gustry thanks for the pointer, I'll check this function

[nworr]

@Gustry that's it !
$dbInfo->geometryColumn = $dtParams->geocol could be used instead of $dbInfo->geometryColumn = $fieldName;

[nworr]

Fixed by #4460