Pathfinding on large map

Question

I\'m creating a game with a 10,000 by 10,000 map.
I would like for a user to be able to set a location and have the computer instantly find the best path.
However, since

Answer 1

This will be a little longer than what fits into a comment, so hence an answer.

Your setup requires clarification. 10,000x10,000 is all good, but this statement is not:

since the map is 10,000 by 10,000, there are 100,000,000 nodes

Why would there be 1 node per each unit of the coordinate system? This is not how node pathfinding works, instead the nodes are supposed to be more sparse, and by their existance describe individual (sparse) points along the path. Between the node points, the object handles movement by other means. A grid pathfinding system might, in worst case (if no obstacles at all), have 100,000,000 points, but as the Q mentions nodes, i assume this is about node pathfinding.

100,000,000 nodes

100,000,000 nodes is 381 megabytes of memory if int32 and 763 mb if float64. In addition, there are node connections. I have no idea how these would be set in your case, but each connection requires 2 integers, say of 2 bytes each. Ie. if there are as many connections as nodes, another 381 mb is needed. All in all, we end up with graph data closer to one terabyte, and i claim that for sure something is wrong then.

How to solve the issue, provided we still have a huge node graph/a huge area? I would probably simplify, by creating larger quadrants (as you mentioned). Each quadrant would however hold nodes only along the 4 edges - all nodes inside a quadrant would be replaced by straight lines. This way, one would resolve the entry/exit points for each quadrant. This would be a separate node graph, for rough calculation. Then, inside a quadrant, one would always load the inner node graph for that quadrant only at time. Ofc there would be some kind of error invloved, but hey, that's reallife, right? If this is about human behaviour, well then it is not always fully optimised.

Pre-calculation, cache, speed, small data are keywords in game coding.