[Openstreetmap] geodriving results

[Zebedee Mason]

Graham

I do find that my Garmin tells me that I've just cycled through a solid 
building in the city. In the countryside it's a bit better. From the 
look of your diagram it would appear that you lost signal on a long 
stretch of the yellow track, the eTrex will note this in its log.

You can actually get realtime data off a Garmin eTrex which includes 
accuracy. Unfortunately this means you need to carry a PDA, laptop, etc. 
at the same time. You are correct in that this information doesn't 
appear to be saved in the tracklog.

HTH

Zeb

Graham Wall wrote:

>A word of caution on accuracy and precision. I've written a little
>about it here, with an example:
>http://www.prizeonion.co.uk/?p=17
>
>Basically - yes, the data looks like it's following a neat path, but
>that path might be reported as being in the wrong place. It would be
>interesting to see what happens if you repeat the same route.
>
>It's a shame that the Garmin protocol and GPX have no provision for
>the reported accuracy of a trackpoint, but repeated observations of
>the same roads will give an indication of accuracy.
>
>Graham
>
>On Apr 6, 2005 9:11 PM, Alex Willmer <alex at moreati.org.uk> wrote:
>  
>
>>SteveC wrote:
>>
>>    
>>
>>>So the past weekend a few of us piled in to a hire car to take some
>>>tracks.
>>>
>>>
>>>      
>>>
>>I've also gathered some tracks, they cover the part of the M1, the M6
>>East of Birmingham, part of the M42, half of the M5 some streets in the
>>North of Birmingham. Long distance stuff was gathered with a bluetooth
>>receiver on the dashboard (even worked with heated front windscreen!)
>>The streets in my immediate neighbourhood were by bike, receiver in bum bag.
>>
>>The logging was performed by cotoGPS running on a Palm, extraction and
>>conversion using pilot-xfer+cotoGPS Desktop on Linux. I've not captured
>>any metadata. The GPX file is here:
>>
>>http://www.alexwillmer.pwp.blueyonder.co.uk/track-trial-20050405aw.gpx.gz
>>
>>Observations:
>>
>>- GPS accuracy is amazing, there's clear seperation where I doubled
>>back, even on narrow streets. For what ever map is produced by us, it's
>>clear wide roads and up will need capturing in both directions.
>>
>>- Capture will have to be systematic for local roads, major roads and
>>motorways are few enough we could capture them in the course of travelling.
>>
>>- As a simple method of keeping track it would make sense to do the
>>edges (major throughfares) and use them as a structure to define areas
>>that can be marked todo -> done.
>>
>>- Simple algorythm for doing an area systematically: keep turning left
>>unless you've done that bit.
>>
>>- For me at least, GPS batteries last much longer than PDA or laptop
>>batteries - use an adaptor
>>
>>- It would be very useful to have a dictation program, audio notes
>>timestamped to the GPS.
>>
>>- Capturing local roads by bike is effective for getting
>>urban-residential raw data, quite relaxing infact.
>>
>>Questions:
>>- Following the SCO and *Alexis de Tocqueville *claims regarding Linux,
>>can we anticipate claims of copyright infringement?
>>- If so, what raw data and documentation (gpx files, notes, diaries,
>>sketches, audio, photos) should be kept to prove clean room
>>reimplementation?
>>- What data, if any, can we avoid gathering on the ground (eg points of
>>interest, street names, road designations, urban/rural land designation)?
>>- What data is available, if any, regarding organisational boundries
>>such as counties and boroughs?
>>- By what standard do we judge a road/track as a public road - ie I took
>>the rule of thumb 'follow the curb, if it's marked private or it's just
>>for parking, don't go there', is that sufficient?
>>- Anyone else doing this in the Birmingham area?
>>
>>
>>_______________________________________________
>>Openstreetmap mailing list
>>Openstreetmap at vr.ucl.ac.uk
>>http://bat.vr.ucl.ac.uk/cgi-bin/mailman/listinfo/openstreetmap
>>
>>    
>>
>
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>
>  
>


-- 
Zebedee Mason
----------------------------
http://www.zebmason.f2s.com/



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