How to find the starting points of the route with a distance of 10 minutes from the target?

Question

Algorithms

Hello!
Do not tell me how you can implement the following:
There is a certain object on the map, for example, a hospital (point 2).

It is necessary to find the most remote points from which this very hospital can be reached in 10 minutes.
To end up with a certain "coverage area" of this very hospital:

I.e. the whole task comes down to finding points that are at a certain distance from the desired one, but the distance should be considered along roads, and not along a straight line.
I would welcome any thoughts on this matter.
Thanks in advance!

Answer 1

Determine the main directions from the point (for example, the widest roads), set aside 10 minutes for them, between them - just approximate (you won’t calculate each lane).
The reverse option - build a circle with a radius equal to the distance in 10 minutes in a straight line (10 km at a speed of 100 km / h), break it into segments, say 10 degrees each (more / less - vary the accuracy), in this segment find the fattest road and already find a route and a point in it.

Answer 2

@GavriKos , thanks for the idea!

Answer 3

if you have free time and want to dig into the APi maps, look towards the problem of exiting the maze:
make a tree with a vertex in your hospital and nodes at intersections, the length of the passage between the intersections will be the length of the edge and apply
the wave algorithm
in the algorithm condition and set the maximum distance => average speed * maximum time (your 10 minutes)