[Qgis-user] Problem with spatial query

[Frank Broniewski]

Hi Anne,

I think, it would be maybe better to use an attribute to link between your lines and the parcels and do a join by attribute instead of join by location. Much less error prone than spatial selection / joinage ...
If your line-layer is derived from the parcels - and it is, if I understand you correctly, you probably have already a common identifier, the parcel id.

HTH
Frank
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Von: QGIS-User <qgis-user-bounces at lists.osgeo.org> im Auftrag von anne söfker via QGIS-User <qgis-user at lists.osgeo.org>
Gesendet: Montag, 25. März 2024 14:24
An: qgis-user at lists.osgeo.org <qgis-user at lists.osgeo.org>
Betreff: [Qgis-user] Problem with spatial query

Hello everyone,

I have a problem with the spatial query or with a link by position. I want to calculate the ratio of the length of the boundary to the street with the area of a parcel. To do this, I have converted the polygons from the parcels into lines, exploded them into individual parts and selected those that lie on roads. These are shown in different colors in the image. Now I want to create a new layer with the link between the boundary length from the layer and the boundary lines (and then calculate the ratio). I have tried all spatial queries here and also under "select by position", unfortunately it does not catch all parcels (yellow marked in the image) that are in contact with their boundary lines. There can be no accuracy error as the lines were generated from the parcels. The lines therefore lie exactly on the respective edges of the parcels. Can anyone give me a tip on how to proceed?

Many thanks and best regards
Anne





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