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cyang-kth / fmm

Fast map matching, an open source framework in C++
https://fmm-wiki.github.io/
Apache License 2.0
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one trajectory not matching #221

Closed rvxfahim closed 2 years ago

rvxfahim commented 2 years ago

I am unable to match one trajectory which looks fine in QGIS over the shapefile in QGIS. Can you please suggest how to match this?

The zip file includes the shapefile and multiple trajectory file and also a single trajectory file.

Here is the screenshot of the result with the single trajectory csv. image

https://mega.nz/file/r8lzCYjY#mejwfdowMc4r9lr4D_rx1X0pPglY6EteKXwQZoBfPNM Thanks.

cyang-kth commented 2 years ago

The file is too big. Please have a look at this issue #138 for the common problems.

rvxfahim commented 2 years ago

I tried most combination. Only didn't try to change delta value. Can you tell me what does delta value mean, and how to choose the value if network is very large?

cyang-kth commented 2 years ago

Please refer to the original paper or docs for your question.

ziXet commented 2 years ago

I tried most combination. Only didn't try to change delta value. Can you tell me what does delta value mean, and how to choose the value if network is very large?

The easiest way to calculate the best value for the delta is the following.

  1. find the maximum time different between two consecutive points in your trajectory. (e.g. 5 seconds)
  2. find the maximum speed of the object (e.g 120km/h ~ 33m/s)
  3. multiply those numbers (e.g. 5*33=165m ~ 0.001 deg = delta)

Hope this hepled.