Questions tagged [relation]
The relation tag has no usage guidance.
48
questions
12
votes
3
answers
750
views
Handling multiple selections result in "Value Relation Widget" in QGIS
Using the "Allow multiple selections" in the "Value Relation Widget" results in {value1,value2,...}. But arrays in QGIS are written like ['value1','value2',...].
How do I handle ...
- 8,338
6
votes
0
answers
273
views
QGIS N:M relations - possibility to edit multiple features?
I have a working QGIS project with multiple relations and all is well until I try the Toggle multi edit mode for N:M relations. I'm working with QGIS 3.10+ (3.14.16) and Windows and PostGIS.
Is it ...
- 194
5
votes
1
answer
442
views
Automatically fill in attributes of parent feature in QGIS
I have a data table that holds different information about buildings in a GeoPackage. Different elements of the buildings can be entered, e.g. sometimes I only have the building as a whole, sometimes ...
- 1,616
5
votes
2
answers
253
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QGIS aggregate - filter by newest date
i have two one-to-may related layers (relation name: tree_observation) parent: trees and child: obeservations. The trees should be revisited on a regular base and for each observation a new child ...
- 3,022
5
votes
1
answer
170
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QGIS - many to many relations - query expression
I have a polygon layer with area geometries of parcels and tables with contracts, with owners / users linked by means of a link table in many to many relationships. This is because some parcels may ...
- 537
4
votes
2
answers
422
views
QGIS Setup n:m relation to enable cross-layer search
In QGIS I want to set up a n:m relation between two tables "parcels" (polygons) and "owners" (no geometry). Both share a field index1 (containing of numbers and letters) by which ...
- 3,022
4
votes
1
answer
403
views
QGIS - Value relation values based on geometry
I am having a problem with last part of defining values in geopackage.
I have created relation values based on field values (drop-down values). Last one I want to create, is to make relation based on ...
- 358
3
votes
1
answer
262
views
Using relations
I am using QGIS, version 3.24.0. I have a shapefile called "Map_CorrectionDEF", uniquely identify by fields "GID" and "unitcode". It is a grid cell, in which the field &...
- 618
3
votes
1
answer
113
views
Counting the number of relations
In QGIS I created a one-to-many relation between a polygon layer and a non-geometry table, so it has multiple lines for each feature in the polygon layer. My question now is how can I count how many ...
- 1,092
3
votes
0
answers
79
views
Using get_feature() function on layer while editing in QGIS
In QGIS, I am trying to update a feature based on entries made on a nested form (relation).
Considering:
Layer1 has Field1 that should capture the value of Field 2, and field in Layer2
Layer2 is ...
- 567
2
votes
1
answer
1k
views
1-n relationship by location in QGIS
I have a polygon layer and a point layer. According to the QGIS documentation, the childlayer has to have a foreign key. Unfortunately, my child layer has none. Is there a way to form the relation by ...
- 3,022
2
votes
1
answer
437
views
Extracting relations with osmnx?
I am using osmnx package https://osmnx.readthedocs.io/en/stable/osmnx.html
to extract data from OSM. I aim to obtain relations from the cyclist node network in Flanders. After some info about tagging, ...
- 21
2
votes
1
answer
441
views
QGIS - Relations - Update parent from child / child from parent
The functioning of my project under QGIS is based on the use of information between parent and child (relation layers).
I need to access specific information to control visibility of containers and ...
- 753
2
votes
1
answer
176
views
QGIS Cloud and relations
Does publishing to QGIS cloud preserve the established relations (1 to many relation) between layers? On the web map, can you see the embedded form of the Parent layer in the Child layer, for example?
- 21
2
votes
0
answers
77
views
QGIS Layer field expression in Polymorphic Relation evaluates to NULL
In QGIS 3.34.3, according to the doc:
Layer expression evaluates to a unique identifier of the layer. This can be the layer name @layer_name, the layer id @layer_id, the layer’s table name decode_uri(...
- 10.5k