Generating network analysis on decoding spaces

I followed a tutorial posted by decoding spaces and managed to create the script without errors but the analysis doesn’t show up on the map geometry. This is the sort of effect I am hoping to achieve:

I Have tried changing the values in the length/curve coefficient and it doesn’t make a difference, same when I tried changing the upper and lower limit of the graph values. There is no effect on the map in rhino as you can see:

Any ideas on what is not working would be much appreciated!

Uploading: picadilly circus 200m radius network map (1).3dm…

accessibility v3 (1).gh (24.4 KB)