[Imports] Non-standard tagging in Spanish Cadastre buildings import

Javier Sánchez Portero javiersanp at gmail.com
Fri Mar 5 13:54:13 UTC 2021


Hello Tobias

I was the developer of the software used for this import currently ongoing
by the Spanish community. Our intention is to improve the map in the best
possible way so I would like to correct the tagging problem you mention. I
will translate this point to the Spanish community to evaluate it.

I would like to denote that this is not an automated import. Since it began
many people have devoted and still makes a big effort to get it done
reviewing and improving each bit of data before uploading it manually.
Although there is a considerable amount of data already imported, there is
still a long way to go to complete the entire amount available.

I could retake the software development in order to correct this issue for
the non completed part of the import as soon as possible.

Regarding the already imported data, I will take a look on ways to correct
it, but take into consideration that it's not an easy task.

A significant amount of the data may have been modified before being
imported due to our data flow that consists of each building being reviewed
by a person before upload. These modifications may include, among others,
topology improvements like deletion of noisy unneeded nodes, checks against
high resolution background aerial imagery that include precision
repositioning or even geometry fixes. So to add the missing building part
it's not only necessary to filter buildings (and its parts) edited after
the import but all those whose geometries differ in the least.

This process would have to be automatic because I do not believe that the
participants in the importation can assume the amount of effort necessary
to review 3 years of editions.

I never developed a project like this correction before, so I would like to
hear more opinions and to see a good consensus about its necessity.

Best regards,
Javier Sanchez

El mar, 2 mar 2021 a las 20:18, Tobias Knerr (<osm at tobias-knerr.de>)
escribió:

> Hi all,
>
> I stumbled upon an issue with the ongoing Spanish Cadastre buildings
> import that was discussed on this list in 2018.[1]
>
> The imported data does not follow the Simple 3D Building tagging
> standard[2]. If a building consists of 2 parts, the import will only
> create 1 building:part area, rather than 2 building:part areas, and
> assumes that renderers will create a virtual building part for the
> remainder of the building.
>
> One of many examples:
> https://www.openstreetmap.org/way/840244312
> https://www.openstreetmap.org/way/840244317
>
> It turns out that deleting these building parts before the import is an
> intentional attempt to reduce the volume of data in the OSM database,
> and is in fact documented on the import's "Data Conversion/Problems"
> subpage:
>
> https://wiki.openstreetmap.org/wiki/Spanish_Cadastre/Buildings_Import/Data_Conversion/Problems#Reduction_of_building_parts
>
> This bit of information is very easy to miss. I certainly didn't notice
> it when first reviewing the import, and I suspect others didn't either.
> If an import intentionally departs from documented tagging practices, I
> would expect this to be given far more attention during discussion of
> the import.
>
> In the interest of consistent tagging, I would like to see this
> behaviour corrected at least for the part of the import that hasn't been
> completed yet, and ideally also for already-imported data that hasn't
> seen any major manual editing since.
>
> Yours,
> Tobias
>
> [1]
> https://lists.openstreetmap.org/pipermail/imports/2018-January/005342.html
> [2] https://wiki.openstreetmap.org/wiki/Simple_3D_Buildings
>
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> Imports mailing list
> Imports at openstreetmap.org
> https://lists.openstreetmap.org/listinfo/imports
>
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