How pcsl maps and dyjkstras algorithm works

 

To enhance this instead of concentrating on nodes we had inward and outward links for each driving direction one way streets had a unidirectional link.

Sorry the picture was done with a text description from claude with multiple arrows per link.

To optimise the route search we only searched within an ellipse where the elipse maximum chord lenght between start and dest node that traced the elipse circumference was about 1.3 times the distance between the start and dest node.

Maybe the elipse can be increased gradually

If the valid route goes outside the elipse and it failed we used another dystras search from scratch without an elipse.

To allocate temporary nodes we used one triple c pointer like ptes in linux.

there are multi storey roundabouts in china so lat long and height above sea level is needed for every junction.