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How to find neighbor polygons in a layer?
There are some use cases where you want to find all neighboring polygons of each of the polygons in a layer. With a little python script, we can accomplish this and much more in QGIS. Here is an example script you can use to find all polygons that share boundary with each of the polygons in a layer and also add their names to the attribute table.
How to get nearest neighbor from different layer?
The result would be a nearest neighbor from the same layer instead of a different layer as we have used here. Once the processing finishes, click the Close button in the Distance Matrix dialog. You can now view the matrix.csv file in Notepad or any text editor.
How to calculate the nearest neighbor in QGIS?
You will see that for every Earthquake feature, we now have an attribute which is the nearest neighbor (closest populated place) and the distance to the nearest neighbor. We will now explore a way to visualize these results.
How to join attributes from nearest point in QGIS?
In QGIS 3.8 and above the “Join attributes by nearest” native tool in Processing Toolbox does the job easily! If you can live with just joining a single attribute from your “B” layer, take a look at the “Hub Distance” tool from the mmqgis plugin.
Here is an example script you can use to find all polygons that share boundary with each of the polygons in a layer and also add their names to the attribute table. As an added bonus, the script also sums up an attribute of your choice from all the neighboring polygons.
How are polygon neighbors reported in ArcGIS Pro?
If the specified fields identify unique polygon groups, the neighboring information is summarized and reported by the groups. See How Polygon Neighbors works for details on the use of this parameter.
When do polygons of the same group have the same field?
Polygons of the same group have the same set of field values. When you need to find the neighbors of each individual polygon in the input, specify an input field that has a unique value for every polygon. In this example, the input table of the nine polygons has a field myCode, which has a unique value for every individual polygon.
How to calculate the area of a polygon?
The detailed workflow is as follows: Select a polygon to use as the source feature. Find all the polygons that intersect the source polygon (find the neighbors). Add the AREA field to the output table. Calculate the area of the overlap. Record the calculated area for use in the output table AREA field.