[talk-au] new face

Andrew Loughhead andrew at incanberra.com.au
Thu Nov 8 11:12:15 GMT 2007

David Groom wrote:
>> ----- Original Message ----- 
>> From: "Eric Rose" <ericr at wamble.net>
>> To: <talk-au at openstreetmap.org>
>> Sent: Thursday, November 08, 2007 9:12 AM
>> Subject: [talk-au] new face
>> Hi,
>> I new here, and just thought I'd introduce myself and ask for some
>> information
>> on how you guys (girls?) do things.
>> Firstly, I'm Eric. I cycle and keep track of my trip stats with a Garmin
>> Edge
>> 305, although I started out using an Etrex Summit, just for my ride diary
>> maps. Recently I also bought a Nokia N800 and have been playing with Maemo
>> Mapper. I have a year and a half of tracklogs from my daily commute and 
>> some
>> cycling around Sydney, along with some longer logs from the NSW Big Ride;
>> all
>> stored on the MotionBased website (motionbased.com).
>> I guess my main question is how you all collect and work on data. Having
>> loaded the track log from the 'Gong ride last Sunday into JOSM, I can't 
>> see
>> any way of turning that one long track into smaller pieces such as
>> individual
>> streets or  roads. Is that necessary?
> The basic principle is that the tracklogs provide an underlying area over 
> which to "trace" the road, using the JOSM draw nodes tool.
> To be honest I'd choose this method first, especially until you are happy 
> with the JOSM tools, and OSM mapping techniques
> If you really want to you can convert a tracklog to data automatically, but 
> unless you have been travelling in one direction along one road, you'll end 
> up with a bit of a mess.  However this "mess" can still be worked on if you 
> like.  What you'd need to do is:
> 1) convert tracklog to data layer - right click on the layer name in the 
> layers panel and choose "convert to data layer".
> 2) split the resulting since way into smaller ways for each road section - 
> highlight a node where you want to split, then Tools>split way 
> 3) tag each resulting way with the appropriate tags
Welcome Eric! I haven't tried this yet - but the online editor Potlatch 
(the flash based editor you get from the "edit" tab on the website) 
apparently has a point reduction algorithm built in when it displays 
tracks.  I think this allows you to utilise the tracks fairly directly 
but without the point bloat that just using raw tracks produces.  But I 
haven't tried it so I may be misunderstanding this a bit. 

The low-tech approach of doing heads up digitizing over the top of 
tracks surprised me when I started in OSM.  I'm still waiting in hope of 
a JOSM plugin that reads tracks, helps eliminate redundant points, and 
turns the remainder straight into ways.  In the meantime the heads up 
approach works well in cities, but can be frustrating when you have a 
beautifully smooth track and just want to turn it straight into OSM data.

>> Do people work on the principle that
>> each street or other line-based features should be collected as individual
>> tracklogs, or do you have some tool that you use to split long tracks (or 
>> is
>> there some trick I don't know about)?
> Tracklogs for a whole area are fine
>> Is it the correct thing to upload whole tracklogs like the Gong ride to 
>> OSM,
>> or should it be preprocessed first?
> Tracklogs should be uploaded to OSM, as they:
> 1) provide evidence of how the data was collected;
> 2) when others upload tracklogs for the same road they allow you to note 
> variances due to GPS errors and correct the original mapping
>> This christmas, I'm planning a cycle trip from Coffs Harbour through 
>> Grafton
>> and Casino to Mullumbimby on the north coast of NSW, along roads that 
>> aren't
>> known to OSM. I'm hoping to fill in a bit more of the area, particularly
>> around the destination if I can get some pointers in how to effectively
>> contribute.
>> Eric
> If you want to do some mapping, and want someone to look over the results 
> let me know the area you've been working in and I'll have a look.
> ( if the main map window shows the area you have been working on you can get 
> the bounding box URL for that area, by clicking the download button (or 
> CTRL-SHIFT-D), choosing the bounding box tab, and copying the URL you see in 
> the box).
> Happy mapping
> David
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