[OSM-dev] Edit question with respect to JOSM changeset representation

[Frederik Ramm]

Hi,

    note that your example is slightly unusual in that you have 
concatenated two ways to form a scenic route but they do not share a 
common node. This is possible but a more realistic example would be

<way id=1>
<nd ref=1>
<nd ref=2>
</way>
<way id=2>
<nd ref=2>
<nd ref=3>
</way>

> Then the user goes ahead and deletes the sidewalk feature meaning 
> deleting way1. What happens to the relation1 and how is the modification 
> expressed in the changeset of the JOSM file format?

JOSM actually lets you do different things, but it never lets you break 
referential integrity. You can delete the way and automatically remove 
it from the relation (leading to a way delete and relation modify), or 
you can delete the relation together with the way (leading to two deletes).

Deleting only the way is not possible.

When uploading changes to the API, JOSM must make sure to send the 
relation modification or deletion before the way deletion, because 
otherwise the way deletion will be rejected by the API as breaking 
referential integrity.

> <node id=1 action=delete>
> 
> <node id=2 action=delete> (which would make way1 being deleted but what 
> about relation1?)

JOSM can delete nodes 1 and 2 for you if you delete the way (unless they 
are still used by something else). In that case the node deletion will 
be added to the list of changes (and sent to the API *after* the way 
deletion has been sent).

But if you are writing an editor then it might not be the grandest idea 
to use JOSM's file format (unless you want JOSM users to be able to 
process the files generated); I would instead store data directly in 
osmChange (.osc) style.

If you really want to interact with JOSM then you could join the 
josm-dev list.

Bye
Frederik

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