Is there a way to count adjacent polygons using QGIS?
I want to create a new field with the number of adjacent polygons.
I want to count adjacent polygons to determine if a polygon (house) is a corner house or an inbetween house.
QGIS Adjacency – How to Count Adjacent Polygons Using QGIS
adjacencycountqgis
Related Solutions
A topological vector model will provide what you need. In a non-topological storage (such as a shapefile), a single edge between geometries is stored twice. In a topological vector, the areas are stored separately from the lines, so adjustments can be made without effecting topology. I couldn't find a good diagram, so I created this simple example, where the areas A, B and C are computed from the intersections of the lines (connecting 1-4) which separate them.
This model is used by ArcInfo as coverages, in GRASS as its default vector model, and can be used in PostGIS with the experimental PostGIS Topology tool. Perhaps a simpler solution is converting your data into linework, removing the redundant segements, and then recreating your polygons after simplification.
Number of points - just simple formula in QGIS field calculator:
num_points($geometry)
See the screenshot below: in this case, the number of vertices of each feature is added to the field "vertex" in the attribute table. Alternatively, you can create also "Create a new field" and get results there.
Best Answer
Using the field calculator, you can use
array_length( overlay_intersects( @layer,""))to identify and count the intersecting geometries