Difference between BFS and Dijkstra’s algorithms when looking for shortest path

Speaking as someone who spent 18 months working at a mapping company, which included working on the routing algorithm... yes, Dijkstra's does work, with a couple of modifications:

• Instead of doing Dijkstra's once from source to dest, you start at each end, and expand both sides until they meet in the middle. This eliminates roughly half the work (2*pi*(r/2)^2 vs pi*r^2).
• To avoid exploring the back-alleys of every city between your source and destination, you can have several layers of map data: A 'highways' layer that contains only highways, a 'secondary' layer that contains only secondary streets, and so forth. Then, you explore only smaller sections of the more detailed layers, expanding as necessary. Obviously this description leaves out a lot of detail, but you get the idea.

With modifications along those lines, you can do even cross-country routing in a very reasonable timeframe.

Dijkstra allows assigning distances other than 1 for each step. For example, in routing the distances (or weights) could be assigned by speed, cost, preference, etc. The algorithm then gives you the shortest path from your source to every node in the traversed graph.

Meanwhile BFS basically just expands the search by one “step” (link, edge, whatever you want to call it in your application) on every iteration, which happens to have the effect of finding the smallest number of steps it takes to get to any given node from your source (“root”).