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#1 2008-05-08 01:26:28

Erik Lundin
Member
From: Göteborg, Sweden
Registered: 2008-05-07
Posts: 22
Website

Always upload GPS trail?

Hi,

Are there any good reasons for uploading the raw data if I intend to do the drawing job myself?

/Erik

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#2 2008-05-08 08:52:18

Lambertus
Administrator
From: Apeldoorn (NL)
Registered: 2007-03-17
Posts: 3,269
Website

Re: Always upload GPS trail?

These are the most important ones:
- Proof that the data does not originate from copyrighted sources.
- Multiple tracks on the same road allows for more accuracy (interpolation) due to the inaccurate nature of consumer GPS devices.


Mapping tools: Garmin GPSmap 60CSx, Giant Terrago 2002

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#3 2008-05-08 09:01:51

Erik Lundin
Member
From: Göteborg, Sweden
Registered: 2008-05-07
Posts: 22
Website

Re: Always upload GPS trail?

Lambertus wrote:

These are the most important ones:
- Proof that the data does not originate from copyrighted sources.
- Multiple tracks on the same road allows for more accuracy (interpolation) due to the inaccurate nature of consumer GPS devices.

Sounds sensible. smile

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#4 2008-05-08 12:02:33

emj
Member
From: .se (59.3N17.99E) 0735969076
Registered: 2006-06-18
Posts: 949

Re: Always upload GPS trail?

I wonder how many JOSM users there are that doesn't upload their tracks.. :-(

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#5 2008-05-08 22:07:48

Hugo_H
Member
Registered: 2007-10-20
Posts: 329

Re: Always upload GPS trail?

Feel addressed by emj as a JOSM user

In some cases I wished they hadn't. GPS tracks with no relation what soever to roads are not helpful. Up loading useless trails does neither help with showing we made the measurement or improves accuracy.

I would like to select the GPS in JOSM I like to use from others, rather then getting the whole heap. They are however downloaded as one layer. Is there a way to split or select them before the down load of Raw GPS data?


Mapping tool: Garmin HCx, Nikon Coolpix L3

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#6 2008-05-09 10:00:23

Lambertus
Administrator
From: Apeldoorn (NL)
Registered: 2007-03-17
Posts: 3,269
Website

Re: Always upload GPS trail?

Hugo_H, I don't really understand what you're trying to say here, but: Uploading a useless trail? What is a useless trail? Also, GPS tracks never have a direct relation with a road other then someone traveled there somehow...

Getting GPX data which is only x days old is currently being discussed on the mailinglists, sorting them by user infringes privacy so that won't happen soon I guess. If you don't want to use other users GPX traces then you can disable that option in JOSM when downloading a certain area, so that is not a reason to tell other ppl to not upload their tracks.


Mapping tools: Garmin GPSmap 60CSx, Giant Terrago 2002

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#7 2008-05-09 17:52:03

Hugo_H
Member
Registered: 2007-10-20
Posts: 329

Re: Always upload GPS trail?

Lambertus, My issue is with blindly uploaded data. Have a look at the GPS trails in this area in Josm with Raw GPS data on (http://www.openstreetmap.org/?lat=52.33 … ayers=B0FT).

It is a well drawn area with few mistakes. However there are lines from GPS data which cross length of 2 km without any reference to a road. As if someone switched his GPS on and off with a suggestion it is a trail. This has nothing to do with your remark on inaccuracy of civil GPS systems. That is normally better then 20 m (or 2 roads wide).

I fail to see what I can do with that kind of "tracks" when drawing a map.


Mapping tool: Garmin HCx, Nikon Coolpix L3

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#8 2008-05-10 00:04:54

emj
Member
From: .se (59.3N17.99E) 0735969076
Registered: 2006-06-18
Posts: 949

Re: Always upload GPS trail?

Hugo_H wrote:

My issue is with blindly uploaded data.
...
I fail to see what I can do with that kind of "tracks" when drawing a map.

Well every piece of data is plus in my book. Of course being able to mark a track as bad (don't show this) would be great. A lot better than filtering  x days old.

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#9 2008-05-10 08:17:11

Lambertus
Administrator
From: Apeldoorn (NL)
Registered: 2007-03-17
Posts: 3,269
Website

Re: Always upload GPS trail?

Hugo_H, look, we agree. I do filter GPS tracks before uploading them, and do not upload tracks GPS tracks that are obviously way off (e.g. perhaps due to a weather front passing). It would be a good thing if everyone uploads only good-quality tracks, but the fact is that not everywhere you have the reference material to determine if your track is reasonably accurate or not. But it requires multiple tracks uploaded in the same area to determine which are good and which are bad. Multiple good ones will give you a better idea about the position of the roads. The tracks that are obviously way off do clutter the editor but can easily be disregarded. That's why I advise to upload every track.


Mapping tools: Garmin GPSmap 60CSx, Giant Terrago 2002

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