[OSM-dev] Tracks without timestamps

Frederik Ramm frederik at remote.org
Wed Jan 10 10:28:49 GMT 2007


Hi all,

    as this is my first post, let me briefly introduce myself: My  
name is Frederik Ramm and I have been interested in mapping and self- 
acquired geodata for a long time (see my 2001 project http:// 
www.remote.org/roadhog/scotland/ and the "making of" pages there). I  
have played around with the "josm" editor and found it to be so well- 
structured and clearly written (thumbs up Imi ;-)) that it was very  
easy to work with as a programmer; I'll probably do some work in that  
area, writing plugins and submitting ideas and patches for josm.

I have seen from the archives that there has been discussion about  
whether the server sould allow tracks without timestamps (it  
currently rejects them).

Just for the record: I am using a recent hand-held aviation GPS, the  
Lowrance AirMap 600C, and this (as well as other Lowrance GPSes)  
cannot be persuaded to save time information with tracks. What you  
get is one initial timestamp when the track begins, and from then on,  
only position data. You can theoretically reconstruct the timestamps  
IF you have the device set to add trackpoints every n seconds  
(instead of every n metres or on every course change).

If I want to upload a track created by my GPS (newer versions of  
gpsbabel can convert the "lowranceusr" format emitted to gpx), I need  
to feed the resulting gpx file through a perl script to create bogus  
timestamps:

#!/usr/bin/perl

$sec=0;
while(<>)
{
     print;
     if (/^<trkpt/)
     {
         $sec++;
         printf "<time>1999-09-09T%02d:%02d:%02dZ</time>\n",$sec/3600, 
($sec/60)%60,$sec%60;
     }
}

Bye
Frederik

-- 
Frederik Ramm  ##  eMail frederik at remote.org  ##  N49°00.09' E008°23.33'






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