Not sure why this neighborhood seems unreachable


#1

I started digging into some failing route lookups and this one seems to be a good example of the issue. Locally, graphhopper fails and says there is no connection to this point, but on graphhopper dot com, it will try to route at least close to the destination. I guess I have to questions: 1) why doesn’t this route to the destination, and 2) if I can’t route to the destination, which setting should I change to mimic the behavior on gh dot com, where it will make a best attempt?

Here are example coordinates: https://graphhopper.com/maps/?point=37.8655%2C-122.26773&point=37.872258%2C-122.073954&locale=en-US&vehicle=car&weighting=fastest&elevation=false&use_miles=false&layer=Omniscale

The entire Rossmoor neighborhood seems disconnected for some reason. I’m new to working with OSM data, so I may be missing something obvious, but it looks like the main road is present in the mapping data

Any help or pointing in the right direction would be much appreciated, thanks!


#2

There is a private barrier: https://www.openstreetmap.org/node/2160544420

https://graphhopper.com/maps/?point=37.876623%2C-122.073169&point=37.875713%2C-122.07377

You can either allow routing through private areas (which we obviously don’t do per default) or remove smaller islands (the area behind the private barrier is routable in itself but disconnected). See https://discuss.graphhopper.com/search?q=connection%20not%20found


#3

Ah, thanks! Do you know what values for prepare.min_network_size and prepare.min_one_way_network_size would most closely mirror the behavior of the public site?


#4

There is no size fits all. For car we use 600 to 800 for both.