[OSM-talk] Big mess- fight or flee?

[Andrew Errington]

Hi everyone,

I have been mapping in Korea a lot.  In July I discovered a problem
because I took a trip to an area I had mapped before.  When I went to use
my new data to check against the map I thought I was going mad.  I was
sure I had mapped certain roads, and they were there on the map, but my
name was no longer in the history.  In fact, there seemed to be only one
version of the road in existence.

Here is one way I know I mapped:
http://www.openstreetmap.org/browse/way/44818037

It was deleted as part of this changeset, which is rather large:
http://www.openstreetmap.org/browse/changeset/7300872

Here's another:
http://www.openstreetmap.org/browse/way/83432223/history

From this large changeset:
http://www.openstreetmap.org/browse/changeset/7575051

I contacted the mapper responsible, who apologised to me and basically
said that they messed something up, or something went wrong during the
editing session, couldn't fix it, so did the best they could to put things
back.

So, I am happy that it was not malicious, but not happy that a lot of my
work (and others' work) has been lost/needlessly altered, and there is no
continuity in the history.  Anyway, I'd like to know what is the best
course of action.  I still have my GPS traces and photos of streetsigns
and other detail, so I could reload it and re-map the area, but it's a big
area...

Should I...
a) Ask someone to investigate what happened and show me what tools to use
to recover/restore deleted data, bearing in mind that the current data
seems to be identical and would overlap restored data?
b) Check/re-map the areas using whatever data I have?
c) Ignore the issue?
d) None of the above

I know that in some ways the database is 'self-healing' since mappers who
spot discrepancies (due to whatever cause) will fix them.  But these
errors don't need to be discovered- I know they are there (and now you do
too!).

I also wonder if there should be some mechanism to stop (or at least draw
attention to) massive edits/deletions before too much time goes by.

Thanks,

Andrew


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Re: [OSM-talk] Big mess- fight or flee?

[Toby Murray]

On Thu, Sep 1, 2011 at 2:20 AM, Andrew Errington
a.erring...@lancaster.ac.uk wrote:
 Should I...
 a) Ask someone to investigate what happened and show me what tools to use
 to recover/restore deleted data, bearing in mind that the current data
 seems to be identical and would overlap restored data?
 b) Check/re-map the areas using whatever data I have?
 c) Ignore the issue?
 d) None of the above

 I know that in some ways the database is 'self-healing' since mappers who
 spot discrepancies (due to whatever cause) will fix them.  But these
 errors don't need to be discovered- I know they are there (and now you do
 too!).

 I also wonder if there should be some mechanism to stop (or at least draw
 attention to) massive edits/deletions before too much time goes by.

There are tools to revert changesets but I think too much time has
passed since this change for them to be used easily since there will
be lots of conflicts with things that have been touched since then. If
the user had asked for help immediately when they noticed the mistake,
things could have been reverted easily.

As for detecting these changes... Do you know about OWL[1]? Although
this may not be much help since it sounds like this didn't happen in
your home area. You can watch change feeds from anywhere but at some
point a large enough area will start to overwhelm someone trying to
watch it.

I personally usually have a copy of LiveMapViewer[2] running at home.
Every once in a while I check on activity I see. I have found a couple
instances of new users being clueless and have been able to contact
them and resolve things quickly. I think that's about all we have at
the moment.

[1] http://wiki.openstreetmap.org/wiki/OWL_(OpenStreetMap_Watch_List)
[2] http://wiki.openstreetmap.org/wiki/LiveMapViewer

Toby

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