[OSM-talk] Retaggin of ways

[Jo]

Jon Burgess wrote:
> On Wed, 2007-12-05 at 17:22 +0100, Jo wrote:
>   
>>>   
>>>       
>> It kind of bother me too that all the roads I touch show up with my name 
>> on them. (I'm touching a lot of them, since I'm using the Yahoo! imagery 
>> to line them up). Now the original editor is not visible anymore in 
>> Osmarender. I suppose it is know somewhere in the innards of the DB 
>> though and only the last person editing is shown for practical reasons.
>>
>>     
>
> You need to be careful about the relative accuracy of different sources.
> I believe that GPS traces are generally more accurate for road positions
> than Yahoo! imagery (especially if there are several GPS traces covering
> the same road). 
>
> Adding roads based on Y! when there are no other traces is fine but
> please don't re-align existing roads just to fit the Y! images. 
>
> The only other obvious exception to this would be with roads consisting
> of very widely spaced nodes. In these cases the roads could be enhanced
> by adding a few more nodes for extra details visible in the Y! imagery.
>
> 	Jon
>   
Quite often they are my own gpx-traces I'm 'improving'. I go in the 
field with the GPS, taking pictures (when by bicycle or on foot) or 
notes (when by bus). Then I enter those traces with josm, merging them 
with the extra info. Then I do a second/third pass to align it all with 
the Yahoo! imagery. Of course, while doing that it's very hard to resist 
the temptation to also change the ways the other local contributor put 
in in 2006. There are not many tracks to go by anyway. He didn't upload 
many and I don't upload all of mine either.

The way I understood it, GPS-tracks can be off for about 10 meters. At 
least, when it's all aligned with the aerial pictures it will be more 
correct and proportional compared with the surrounding streets and 
features. Even if it's off a bit, it will be good enough for the time being.

Jo