The concepts seem at first glance to be similar, but I think the main difference is that Ambulate emphasizes creating a map that can be used for actual navigation along side the itinerary (plotting routes and adding map markers).

Wanderlog seems to be more about organizing the overall activities, where the travel activities are just points on the itinerary, e.g. get a flight from A to B.

Copyright is updated, thanks for pointing that out!