Understanding the effect of limited precision GPS data on speed distributions

April 29, 2015/0/0
Home / Understanding the effect of limited precision GPS data on speed distributions / Understanding the effect of limited precision GPS data on speed distributions
gps_precision

I’ve been looking at speed distributions derived from GPS tracking data. When I started to see some strange peaks in the distribution, I investigated to see if they were being caused by the limited precision of my GPS coordinates (My east/west readings were on ~1m precision, but north/south coordinates to only ~11m.)

Take a look at this notebook, where I:

  • I create a set of random single tracks in a 100 x 100 box (pairs of x, y, coordinates).
  • Look at the distribution of their lengths
  • Apply a truncation  to limit the coordinate precision.
  • Look at the new distribution of lengths.
  • Attempt to reverse the effect of the limited precision, in order to reproduce the distribution original shape.

In conclusion I found this effect was responsible for the peaks!

Navigation

Add comment

This site uses Akismet to reduce spam. Learn how your comment data is processed.