Networkx's touch return False while 2 polygons share some edges

[nmcdtu]

I want to test if some polygons touch the others to create a map with different colors for different regions, by using greedy_color (with networkx 3.3).

Here is a reproducible example:

import geopandas as gpd
import networkx as nx

gdf = gpd.read_file('BlackSea_0.json')

# Create an empty graph
G = nx.Graph()

# Add a node for each polygon
for index, row in gdf.iterrows():
    G.add_node(index, polygon=row['geometry'])

# Test if the 2 polygons touch
G.nodes(data=True)[0]["polygon"].touches(G.nodes(data=True)[1]["polygon"])

I attached the screen capture

and the sample data BlackSea_0.json
As you see, the 2 polygons share the some edges.
But the test above returned False.

I was wondering if I misunderstood something?
I really appreciate if someone can explain it to me, thank you!

[dschult]

It looks like the key function/method here is .touches which is not a networkx function/method. I guess that it is a geopandas method.

You can cut to the heart of the issue without using networkx:

import geopandas as gpd

gdf = gpd.read_file('BlackSea_0.json')
p0, p1 = gdf['geometry']
p0.touches(p1)   # returns False

[nmcdtu]

Thank you for your answer!
Yes, as you wrote, the test did return False.

Should I report it in geopandas Github repository?

[nmcdtu]

I replaced touches with intersects, and as far as I see, everything worked as expected!

G.nodes(data=True)[0]["polygon"].intersects(G.nodes(data=True)[1]["polygon"])  # return True

Thank you very much!

[dschult]

Glad you found a solution.
I will close this conversation. :)