[OSM-dev] Edit question with respect to a changeset representation
temge at esri.com
Fri Mar 19 00:16:16 GMT 2010
Thanks for the clarification, Frederik.
Yes, I am writing my "own" editor. Based on the description at http://wiki.openstreetmap.org/wiki/OsmChange I had assumed that those formats can be used interchangeably.
I am not insisting on using the JOSM format - if there is another, more suitable, format then I will change the approach for my editor.
That said, would the approach be different when using the osmChange style as compared to your answer for the JOSM format below? In other words it is the responsibility of the editing client to maintain integrity, correct?
You've also mentioned that the order of sending the updates is important. Can all three "actions" be included in the same file and the order in the file is important
or do they need to be issued different requests for each action type.
I am thinking of the following scenario. I am starting out with a closed way
And the after the modifications the new way looks like
In such a way that N2 was modified and N-1 was created.
The first update against the server would be
All the changes are accepted and now with (node, old_id=-1, new_id=5) the next update would be
<nd id=1 />
<nd id=5 />
<nd id=2 />
<nd id=4 />
<nd id=3 />
<nd id=1 />
From: Frederik Ramm [mailto:frederik at remote.org]
Sent: Thursday, March 18, 2010 3:58 PM
To: Thomas Emge
Cc: 'dev at openstreetmap.org'
Subject: Re: [OSM-dev] Edit question with respect to JOSM changeset representation
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
> 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
> <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
Frederik Ramm ## eMail frederik at remote.org ## N49°00'09" E008°23'33"
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