[josm-dev] JOSM file format extensions

[Frederik Ramm]

Hi,

Sebastian Klein wrote:
> Compared to that, the JOSM format is quite minimalistic. It just adds a 
> action=* attribute and thats it. But it reflects much better, how the 
> application "thinks". And it is very similar to the "standard" osm 
> format and thus, can be processed by osmosis.

Actually this is something that many people trip over: "oh, it looks 
just like a normal OSM file, let me use it as one" - and then things 
don't work because of negative IDs, or (even worse) they use osmosis to 
merge two files with negative IDs (of course the IDs are used for 
different objects in both), or they process the files in an application 
that does not understand the way JOSM records object deletions (and then 
are surprised that all the deleted objects show up again)...

> We could use the osmChange format, but then we would need to put the 
> normal osm data and the osc change data in a zip-archive. I'm not sure 
> this would be an improvement.

Probably right; if we wanted to use osc alone we would again have to do 
dirty tricks like adding a "create" record for each existing object or so.

The more I think about it the less I like using an existing format. I 
think that using <osm>...</osm> has problems (noted above), and you are 
right in saying that <osmChange> is not better.

If JOSM used a special JOSM format which other software would not 
recognize, then we could provide import and export functions or 
converters that would make sure that things are handled correctly, e.g. 
that if you export from JOSM to an <osm> file all objects marked as 
deleted will not be exported, and so on. People would not be tempted to 
think "oh, it's an OSM file, I can use it with the XYZ application".

Bye
Frederik

-- 
Frederik Ramm  ##  eMail frederik at remote.org  ##  N49°00'09" E008°23'33"