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bmwcarit / barefoot

Java map matching library for integrating the map into software and services with state-of-the-art online and offline map matching that can be used stand-alone and in the cloud.
Apache License 2.0
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Less u-turns #62

Closed kozyr closed 7 years ago

kozyr commented 7 years ago

Hi, I'm looking to see if I can use barefoot for my projects, and run into this in my first test. My raw data is as follows image and when I match, I get points onto Kurze Muhren (point 27), which was actually never driven on. Is there a way to match point 27 onto some other road (Bransende in this case)? I'm running everything right now with default parameters.

smattheis commented 7 years ago

You have quite large deviations of GPS positions, probably because of the buildings. You could try increasing the matcher.sigma value to, e.g., 8 meters.

kozyr commented 7 years ago

Tried it with 10 meters as matcher.sigma, but it still picks Kurze Muhren...

smattheis commented 7 years ago

Could you please provide the raw data in the format JSON format required by Barefoot?

kozyr commented 7 years ago

Sure. The point that goes to Kurze Muhren is with datetime of 1475684525936

hamburg1.txt

smattheis commented 7 years ago

Okay, I just checked back and got a path without Kurze Mühren if sigma is set to 15 meters, but I think some other matches will fail then especially because this is in a dense city area. Instead of increasing sigma to some large value I would try to increase the data quality, e.g., with heading information, or data quantity, e.g., higher frequency of position measurements.

kozyr commented 7 years ago

Ok, thanks. This data though comes from normal consumer phones, and it's not practical to sample them more often than once every couple of seconds. I could get the heading information off the phone, but not sure whether that would help here..

smattheis commented 7 years ago

Are the users walking or going by car. If by car, heading will help.

smattheis commented 7 years ago

I'm closing this issue due to inactivity, please reopen it if there is more on that.