Find point where touching geometries touch each other

Question

I have a GeoDataFrame with LineStrings and want to get all coordinates where the Geometries touch each other. I can find the ones who touch each other so far but how do I get the coordinates of the touching point? It should be as fast as possible because I have a lot of data.

data = gpd.read_file("data.geojson")
heads, tails = data.sindex.query_bulk(data.geometry, predicate="touches")
touching_dataframe = data.iloc[heads]

Asked By: Kewitschka

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Source

Answer 1

Use the intersection method provided by shapely library which is a dependency of geopandas.

# create a list to store the coordinates
coordinates = []

# iterate over the indexes of the touching geometries
for i in range(len(heads)):
    # get the geometry of the current touching pair
    head_geom = data.iloc[heads[i]]['geometry']
    tail_geom = data.iloc[tails[i]]['geometry']
    
    # get the intersection of the two geometries
    intersection = head_geom.intersection(tail_geom)
    
    # add the coordinates of the intersection to the list
    coordinates.append(intersection.coords[:])

# create a new dataframe with the coordinates
touching_coordinates = pd.DataFrame(coordinates, columns=["longitude", "latitude"])

You will have a new DataFrame with all the coordinates where the geometries touch each other. Note that this process can be slow if you have a lot of data, so you should consider to use multiprocessing techniques or Dask to perform this operation in parallel.

Answered By: Serge de Gosson de Varennes

Find point where touching geometries touch each other

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