problems with GPS traces

Posted by vVvA on 2 July 2011 in English (English)

i have been uploading my gps traces, made with a garmin etrex device, but they seem to display in a wrong way in the osm map. sometimes they even make crash the online editor. i am not sure what is wrong with them. any advice is appreciated. thanks

Comment from Anna_AG on 3 July 2011 at 22:53

I downloaded the last two sets of traces that you have uploaded - JOSM was happy with them no issues ( 20110630.gpx & 20110625.gpx ) so not sure what the problem with PL2 if any.

Your traces seem to be a little noisy ( possibly due to being in a built up area ) - and this part of Harvard Campus has excellent BING imagery which will always tend to have a better accuracy than GPS traces and more useful for absolute mapping purposes.

The Garmin Etrex units (depending on which one you have ) have a couple of options on how they store tracks.

The best setting for mappers is to set the units to cache your location every 1/2/5 seconds etc ( I personally cache on 1 second ) using a Garmin HCX Legend with a 2GB memory card. If you have an original Yellow Garmin Etrex, you will not have this option, and you are stuck with the Garmin caching technique, that when it detects that you have made a significant move from your last cached point, or are making a direction change. it is an efficient approach in terms of data storage, but can lead to rather untidy tracks especially when you are walking.

To Clean up GPX tracks before uploading can sometime be useful, especially if you have left the GPS unit on ( perhaps at home or work ) and you find a large cluster of noisy points etc. I usually drop my GPX tracks into JOSM and use the plugin EditGPX to tidy up a trace before upload. You can also merge a number of tracks down into one layer thus saving you multiple uploads of smaller GPX tracks.

You have highlighted a another problem - but I think that needs a new Diary entry
Good luck and enjoy making your traces - have a play with JOSM and some of the plugins, I am sure you will find them useful

Comment from vVvA on 13 November 2012 at 06:43

thanks. this is very helpful. sorry it took me so long to reply. even though i have continue uploading traces i didn't notice i have a comment in my diary. i think i am going to start using the josm editor.

Comment from Anna_AG on 13 November 2012 at 09:36

Hi vVvA The JOSM editor is very powerful and there are lots of ways for you to customise it. I have been using it nearly every day for about 3 years - it is very stable, very good.

If you need any assistance with it let me know and I will try to assist you

Best regards


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