[Talk-ca] Importing buildings in Canada

[John Whelan]

I'll cross my fingers and hope it all comes together.

Thanks John

Tim Elrick wrote on 2020-01-15 5:18 PM:
> Hi all,
>
> I understand your concerns, John. However, many mappers might not 
> follow talk-ca. So, I guess, Daniel's suggestion to contact them, 
> might work better than waiting for them to incidentally check talk-ca.
>
> * More to finding local mappers *
> By providing the overpass query I just wanted to share a different way 
> of contacting active mappers in your area. The advantage of Pascal's 
> Who's around me is that you can see the mappers with lots of 
> changesets, ie. presumably experienced mappers. The disadvantage is 
> that these changesets do not have to be from the area we are 
> interested in (however, with activity center in the last 6 months we 
> at least make sure they were working in our area); another 
> disadvantage is that you cannot collect the names of the mappers 
> easily (or am I missing something here?). The advantage of the 
> overpass query is that you get that list of names easily and you can 
> see how many objects they have added in your area in the past months. 
> The disadvantage, of course, is that we don't know how experienced the 
> mappers are (but maybe this doesn't matter).
>
> Anyway, either approach works as Daniel already pointed out. Thanks to 
> stevea, I now know that I can share Overpass queries easily:
> for a geocoded area:
> http://overpass-turbo.eu/s/PM9
> for a bounding box:
> http://overpass-turbo.eu/s/PMb
>
> * Contacting local mappers *
> I suggest we design a template letter on the wiki page that can be 
> send out to local mappers that include the everything that Daniel 
> suggested in his last message below.
>
> Tim
>
>
> On 2020-01-15 15:54, Daniel @jfd553 wrote:
> Hi John, Tim, and the others :-)
> John, I understand your concern and if it was not addressed properly, 
> this could block the import again.
>
> IMHO, we just need to make sure that we have done everything 
> reasonable to inform the concerned contributors, in order to discuss 
> the import in case they do not agree with it. That is why I proposed 
> the following, in a previous email, concerning local mappers buy-in…
>
> 1- We contact them to explain our intentions by referring to the 
> appropriate wiki pages.
> 2- We wait a week or two for them to respond to nothing, have concerns 
> or want to help.
> 3- Without negative answers, we could proceed to the import.
>
> The point 3 above make sure the project is not stalled in case there 
> is no or only a few answers. The identification of local contributors 
> using Neis’ tool, or the query Tim Elrick just proposed, are what I 
> consider reasonable attempts for contacting the local mappers.
>
> Daniel
>
> -----Original Message-----
> From: Tim Elrick via Talk-ca [mailto:talk-ca at openstreetmap.org]
> Sent: Wednesday, January 15, 2020 15:12
> To: talk-ca at openstreetmap.org
> Subject: Re: [Talk-ca] Importing buildings in Canada
>
> Hi all,
>
> *a) data hosting*
> I can offer to host pre-processed data for the building imports as well.
>
> *b) task manager work units*
> I find smaller tasks about 20 minutes each more appealing than 1 hour 
> tasks
>
> *c) checking already existing data*
> An added tag would certainly help as you can apply a filter in JOSM then.
>
> *d) finding local mappers*
> You can use the following query on http://overpass-turbo.eu/ to get a
> list of all users in the time period specified in the area specified.
>
> // overpass query
> [out:csv(::user)];
> // replace Montreal by any known location in OSM, or see code below
> // for bounding box use
> {{geocodeArea:Montreal}}->.searchArea;
> (
>     // I collected users active in the last 6 months, but you can
>     // change that
>     node(newer:"{{date:6 months}}")(area.searchArea);
>     way(newer:"{{date:6 months}}")(area.searchArea);
>     relation(newer:"{{date:6 months}}")(area.searchArea);
> );
> out meta;
> // end overpass query
>
> Copy the query into the left side of the window and click Export, then
> 'raw data directly from Overpass API'. This will generate a csv. You can
> then count the number of times a name appears in your list by using
> LibreOffice, R, Python or Excel. This will give you the number of
> objects a user entered in the last 6 months.
>
> If I do this for Montreal I end up with 106 names who have contributed
> 20 objects or more in the last half year or 46 names who have
> contributed 100 objects and more.
>
> You can then use https://www.openstreetmap.org/message/new/USERNAME by
> replacing USERNAME with the names from the list to contact these users.
>
> For areas where there is no geocodeArea in OSM you can use the
> boundingbox query below. First, zoom to the area of interest (i.e. your
> bounding box), then paste the following code on the left and export:
>
> // overpass query
> [out:csv(::user)];
> (
>     node(newer:"{{date:6 months}}")({{bbox}});
>     way(newer:"{{date:6 months}}")({{bbox}});
>     relation(newer:"{{date:6 months}}")({{bbox}});
> );
> out meta;
> // end overpass query
>
> Tim
>
> On 2020-01-15 12:55, Daniel @jfd553 wrote:
> Thanks for the quick replies!
>
> Now, about...
>
> *a) Data hosting:*
>
> Thank you James, I really appreciate your offer (and that of others). So
> yes, I think hosting pre-processed data in the task manager, for
> approved regions, is an attractive offer. When we agree on a
> municipality for pre-processing, I will contact you to make the data
> available.
>
> BTW, I thought ODB data in OSM format was hosted with the OSMCanada task
> manager. I understand that ODB data are currently converted on the fly
> when requested?
>
> *b) Task manager work units for import:*
>
> I agree with Nate, ~ 200 buildings or ~ 1,500 nodes would be suitable. I
> was thinking at the same importation rate, but for an hour of work. It
> seems best to target 20-minute tasks.
>
> *c) Task manager work units for checking already imported data*
>
> According to Nate, it is definitely not faster than actively importing.
> We should then keep the above setup (b).
>
> However, what if I add a new tag to pre-processed data indicating if a
> building was altered or not by the orthogonalization (and
> simplification) process? For instance, /building:altered=no/, would
> identify buildings that were not changed by the process and that could
> be left unchanged in OSM (i.e. not imported); /building:altered=yes/ for
> those who were changed by the process and that should be imported again.
> The same pre-processed datasets could then be made available for all
> cases. Thoughts?
>
> *d) Finding local mappers:*
>
> I agree with Nate’s suggestion to try contacting the top 10 mappers in
> an area. Using the "main activity center" would work for most of the
> contributors but selecting other overlays (.e.g. an activity center over
> last 6 months) could also work great. As long as we identify who might
> be interested in knowing there is an import coming.
>
> Comments are welcome, particularly about the proposal on c)
>
> Daniel
>
>
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