[OSM-dev] Source tag on each node

[Wyo]

Alan Mintz wrote:
> At 2010-12-19 00:59, Wyo wrote:
>> I've just realised that rather many nodes have their own source tag, even
>> if they are just part of a way with identical tag. So I guess a rather
>> large part of the data consists of these source tags. While this isn't a
>> problem for files (thanks to compression) it enlarges the database quite a bit.
>>
>> Are these tags really necessary or could they be remove as long as the way
>> has a source tag? Could anybody provide an estimate how much space
>> reduction could be gained? Could anybody create a report on how many nodes
>> have identical tags as their way?
>
> Do you have an example?
>
See http://www.openstreetmap.org/edit?lat=47.17473&lon=4.71559&zoom=17 where the 
nodes of the canal way have identical values.

> I tag intersections of ways as I survey them with source=*, source_ref=*
> among other things, like signalling, turn restrictions, etc. Sometimes, the
> source value is the same as that of the way, but that is only coincidental
> - it's not a duplication.
>
Sorry I don't understand that. Since nodes obviously inherit (by understanding) 
anything from their ways, the values either must be different to show different 
info or they don't carry any info.

Wyo