Re-visiting OSM

Posted by petphi on 27 November 2013 in English (English)

24 November 2013: After a substantial break, I've returned to OSM to do the following: a) add new roads in the development areas of Torquay b) clean-up non-tracks and re-add a couple of deleted real tracks in the Anglesea Heath c) re-load five years worth of (now anonymised!) GPS traces from my original mapping of the Surf Coast. This covers almost every road and street from Torquay to Apollo Bay and beyond, with the exception of Anglesea township. It includes large swathes of (official, Parks Victoria) 4WD tracks through the Great Otway National Park. Continued journeys over the years have provided multiple traverses of all but the most tricky tracks that I could persuade my trail bike to cover. The 5 "traces" I've uploaded (1 per year) contain 144 trips, and 330000 points; it's surprising how these things add up, without trying!

Location: Jan Juc, Torquay, Surf Coast Shire, Barwon South West, Victoria, 3228, Australia

Comment from Vincent de Phily on 27 November 2013 at 13:35

Welcome back, hope you like the progress made in two years :)

Comment from Rhubarb on 27 November 2013 at 14:27

Awesome :)

Earlier this year I mapped out the Parker Hill campsite, I didn't get much of an opportunity to walk more than 100m of trails, but I did mark the location of 2 fluker posts in the area, eg

It's always great to hear (and see) gradual improvement for some good holiday locations in Victoria :D

Comment from petphi on 28 November 2013 at 11:34

#Thanks for your comments!

Vincent de Phily: I noticed quite a few details have been added in my home area. Good to see, as it was pretty bare when I started in 2009.

Rhubarb: There were no good maps of the official 4WD/offroad trails in the area when I started. Great to see that my desire to have accurate maps on my Garmin can benefit others who holiday in the area. *You've given me the idea of adding the fluker posts from around here too.

Comment from malenki on 30 November 2013 at 10:26

Welcome back mapping!

A detail I'd like to mention: When I hike one week, I have a log with ~100k-140k points (logging 1 point/s). Regarding this, 330k points for 144 trips seems a little sparsely to me (but still better then nothing ;) ). Maybe you could set up your device to log a little more verbose?

Comment from petphi on 30 November 2013 at 11:27

Hi Malenki.

Thanks for your input, you make a good point. It reminded me to check the recording settings on my Garmin GPSmap 60CSx ("Auto" and "Most often"). I set it up this way because when I am out-and-about, I tend to stop a lot (taking photographs, looking at birds), and I found cleaning up spurious points was very annoying.

Analysing a recent track log, I calculated an average of 5.5 second intervals between points, but that doesn't tell the whole story; it is often 1/s when travelling at anything over 15km/h on my motorbike. In terms of usefulness for mapping, it turns out to be sufficient, particularly because multiple trips over the same roads (over many years) gives me an averaging effect with the GPS traces.

Thanks for your handy tip though - I might do some more experimenting with the recording intervals.

Comment from petphi on 30 November 2013 at 11:45

A further note to Malenki: After my statement about averaging GPS traces (now that it's a few years "down the track"), a quick review in OSM or JOSM makes me realise that I have to re-edit some of the initial tracks that I drew with a single trace, now that I have better data. Thanks again for reminding me to review my OSM practices!

Comment from malenki on 30 November 2013 at 16:51

You are welcome.
I have also realised that I have to remap quite some stuff I mapped times ago either without much source data or with bad mapping practice.

You can also set your GPSMap to log each 0.02km or so. This would combine a dense collection of points while moving with avoiding point clouds (hopefully).

The automated logging settings (often, most often and such) I dropped as soon as I explored my first Garmin device since this setting generated even in the most verbose setting clearly too little data.
Since there is no real space limit for logging on Garmin devices I'd try to log as much as possible. If one thinks the data too dense afterwards it can always get cleaned using gpsbabel.
But still there is no useful tool to remove cloud points automatically.

Comment from petphi on 1 December 2013 at 08:14

Malenki: Thanks again - a great tip. I tried the 0.02km setting on a car-drive around one of my regular "exploration" locations, and it was perfect. I was able to record a nice smooth trace, and yet it eliminated the point-clouds when I stopped to take photos. Excellent advice!

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