Really good question and to be honest I do not know. I thought that e.g. a weighting with foot which is much less hierarchical than with car will always give more visited nodes but (from a few examples) I think this is not true.
Following things are important:
- get getMinWeight right not too high and not too low as either performance is not optimal or correctness.
- reduce the number of possible ways as much as possible and move all calculation out of the Weighting in a preprocessing (of course, this does not affect the number of nodes)
- the more landmarks the better
- maybe you try manually picked landmarks (prefer those at the border of your area). But highly likely our automatic detection algorithm is already very good here.
- Try changing the active landmarks, although here the defaults should be good already