How to compare two layers and find the differences between them?

The answer is a tool: Detect changes in the dataset in QGIS.


I have a layer of parcels from PODGiK from 2021 and parcels from PODGiK from 2022. I want to check the differences between them, e.g. changes in geometry (parcel splits) or changes in attributes (changes in numbering)


The tool is designed to compare two different versions of the same dataset. It will most likely not help in comparing water supply network data from PODGiK with data that “someone once” digitised.

Principle of operation:

This algorithm compares two vector layers and determines which features remain unchanged, added, or removed between them. Depending on the comparison settings, the comparison will be performed using exact comparison (where the geometries must match exactly, including the order and number of vertices) or topological comparison only (where geometries are considered equal if all their component edges overlap, e.g. lines with the same vertex positions, but opposite directions will be considered equal in this method). If the topological comparison is chosen, any z or m values present in the geometries will not be compared.
By default, the algorithm compares all attributes from the original and revised features. However, you can turn off attribute comparison or leave only those attributes that are relevant to your comparison.
If any features in the original or revised layer do not have associated geometry, ensure that these features have a unique set of attributes selected for comparison.
The algorithm generates three layers:

  1. containing all the features that are considered unchanged between versions,
  2. containing features removed from the original layer that are not present in the revised layer,
  3. containing features added to the revised layer that are not present in the original layer.


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