[Imports] Fixing large number of mistagged buildings near Boulder Colorado, US

[Chris Riddoch]

Okay. To those who pointed out that I don't want to revert: you're
absolutely right, I don't.  The building outlines are fine.  A few of
them have already been retagged appropriately by other users.  And
yes, a good point was made that the original contributor may be more
willing to work on fixing it than I'd expect.

I identified the buildings affected by a combination of queries I
wrote by hand against a local PostGIS instance - I first set QGIS to
color ways according to the building type, then I added another layer
to change the fill according to another attribute, which I tweaked and
compared visually until the buildings that needed to be changed had
both attributes.  Now that I understand how changesets are
represented, it will be possible to cross-check against the
contributor.  By varying color the according to building type in
combination with a second attribute I was manipulating, it was much
easier to identify the list of buildings needing changes.  I was then
able to produce a query to give me the list of way IDs needing
changed.

The text of https://wiki.openstreetmap.org/wiki/Automated_Edits_code_of_conduct,
Import/Guidelines, Automated_edits, and Bots left me with the
impression that there was a need to create a tool to help with
reverting things when they need to be - and I agree, there's no need
in this case.  I'm not sure what specifically needs to be changed on
those pages, but they certainly left me with the impression that
reverts are inconveniently difficult.

The next chance I'll have to spend time on this will be sometime next
week.  I'll contact the original contributor, and go from there.

Thanks for your help, everyone.

On Tue, Sep 8, 2015 at 2:42 PM, Paul Norman <penorman at mac.com> wrote:
> On 9/7/2015 9:49 PM, Chris Riddoch wrote:
>>
>> I would also have already written an automated edit script, but I saw
>> in numerous places of the wiki, as well as being told indirectly on
>> IRC, that I should really be talking to someone about this sort of
>> thing first.  I looked through what documentation there is about the
>> 'osmchange' format on the wiki, but it wasn't clear how to handle
>> changes to tags from the description there.
>>
>> So I ran josm with -Djavax.net.debug=all so that I could analyze the
>> format properly.  It looks like it isn't *quite* as simple as just
>> providing a file you can just send to the server, because that
>> incorporates a changeset ID which is ephemeral.  I also wouldn't want
>> to try such a thing without properly testing it first.  So I knew I'd
>> need to talk to someone here about how best to do this -- thus, my
>> original message.  I came here because I read those wiki pages.
>
> Generating the diff yourself and uploading is the wrong way to make a change
> like this. The normal way to deal with a change like this is with JOSM and
> JOSM's find command, perhaps combined with the overpass API. I should
> mention that overpass API and "select all" is not the right way to make a
> change either.
>
> There are exceptions to this rule, such as a mechanical fix of TIGER street
> names from about a year or two ago, which was both large and complex.
>
>> Yes, it's *possible* to fix errors by hand individually using JOSM, in
>> the same way it's possible to count grains of rice by hand, but... no,
>> I'm sorry, I'm just not motivated to do that.
>>
>> It sounds like the most useful thing I could do, though, would be to
>> help you all develop a mechanism for reverting changesets.  That seems
>> a rather important feature for crowdsourced data management.  Should I
>> be
>> looking at https://github.com/openstreetmap/openstreetmap-website for
>> that?
>
> Openstreetmap-website is for the web page and API, and revert tools wouldn't
> be part of either. They interact with the API like other editors. JOSM has a
> revert plugin, and there are also command-line tools which are difficult to
> use. Improvements to either of them would of course be welcome.
>
> A revert isn't what you want anyways, if they were mapped with the wrong
> building value from the start, as reverting the changeset would remove them
> all.
>
>
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-- 
Chris Riddoch
http://www.syntacticsugar.org/