[OSM-talk] osm-filter.pl observations

[Lars Aronsson]

Andrew Loughhead wrote:

> One usage error I initially made was in filtering data I 
> collected on a dual carriageway. I had two gpx files, one for 
> each direction. If I ran both files into osm-filter.pl at once, 
> it thinks there is only one road.

This is of course a matter of error margin.  How much must two 
roads be separated before they are considered to be two roads? If 
the tracklog contains error estimates (HDOP, VDOP, number of 
satellites in view, degree of sky visibility), that provides a 
clue.  But even then, you can have a bikepath running next to a 
major road all within a 5 meter error margin.

Perhaps it is not all together bad to conclude, in the first step, 
that they are one road. In the second step, if many tracks are 
available for the same piece of road, when further analyzing the 
characteristics that road, statistics about speed and driving 
direction can be correlated to position.


-- 
  Lars Aronsson (lars at aronsson.se)
  Aronsson Datateknik - http://aronsson.se