[Talk-dk] mapping activity

Fre Jul 30 09:41:56 UTC 2021

Hi Sonya,

On 29/07/2021 08.22, Sonya Khilchyk via Talk-dk wrote:
> In July our team is going to start a mapping project in Denmark.
> We would really appreciate your feedback, any questions you have about
> this project, as well as local insights that you think will help us
> better understand the data.

Thanks for the information, and welcome to the Danish OSM domain. I
believe the community will be supportive of your organised editing
project, if it is done with attention and not mess too much around with
established conventions ;).

I did some minor edits to the [project page][1] yesterday for layout and
adding references to, amongst others, this mailing list thread. Hope you
regard them as adding value to the information.

I see that you added the project to "Current mapping projects" on the
[main Mapbox wiki page][2] this morning too. Shouldn't the project page
also be contained in the wiki space "Organised_Editing/Activities" like
previous linting projects, fx. the latest [Italian project][3] completed
in June?

I think some more information regarding the SDFE imagery and data that
Michel and Anders mentioned would be beneficial for you, so here goes;

The yearly spring fly-over is organised in a cooperation between
municipals (represented by an entity called [GeoDanmark][4]) and the
state (the mentioned SDFE, which in English is "The Danish Agency for
Data Supply and Efficiency"]). SDFE's English homepage [contains a a
generic description][5] of the dataset, but there are much more
information on the [Danish equivalent][6], if you dare go there with an
auto-translator.

The imagery is directly available in WMS services offered from two
parallel data providers known as ["Datafordeleren"][7] ("Data
Distribution Platform") or ["Kortforsyningen.dk"][8] ("Danish Map
Supply"). The service lists linked above will have entries for the
imagery named something like "orto_foraar" or "GeoDanmark ortofoto".

A Danish geo company and OSM supporter, Septima, maintains [a WMS->TMS
proxy/gateway][9] making it possible to consume the imagery directly as
a TMS service without authentication in OSM tools such as iD and JOSM.
The Septima TMS service is included in the "editor-layer-index" project
as ["SDFE aerial imagery"][10] and connected to Danish territory. This
project is used by editors such as JOSM and iD in their standard
configurations to present relevant layers, and maybe choose a default,
for edits in specific territories. So if you are using JOSM or iD you
will mostly likely be seeing the "SDFE aerial imagery" imagery already.

Note that the latest recorded dataset is offered in a preliminary
non-correceted service known as "orto_foraar_temp" or "GeoDanmark
ortofoto, midlertidige", sometimes also referred to as "quick". This is
more recent but is [only coarsely corrected for geometry and color][11],
but looking at it through the [SDFE map viewer][12] can be a useful
addition to the corrected layer as overlay in the editor.

SDFE also offers a service known as "Skråfoto" ("Oblique photos"),
showing a location from all 4 headings. This is only available as a [web
page][13] but can be of great help in determining a locations exact
properties.

In addition to imagery SDFE also supplies a service exposing official
street addresses. These are continuously imported and updated into OSM
by a bot named [AutoAWS][14], the wiki page contains more technical
information.
In general, street address nodes in Denmark should not be touched by
human mappers, and street addresses should not be added to buildings as
this will create duplicate addresses. This is why address nodes are
strictly separated from other OSM objects. Moving any street address
node will cause the bot to move it back to the official location at its
next pass.

Hope this will help your team in their quest.

-- 
Regards,
Mikkel

[1]:
https://wiki.openstreetmap.org/wiki/Resolving_lintings_problems_in_Denmark
[2]: https://wiki.openstreetmap.org/wiki/Mapbox#Current_mapping_projects
[3]:
https://wiki.openstreetmap.org/wiki/Organised_Editing/Activities/Resolve_linting_issues_in_Italy

[4]: https://www.geodanmark.dk/
[5]: https://eng.sdfe.dk/products-and-services/photos-and-geodanmark-data
[6]: https://sdfe.dk/saadan-arbejder-vi-med-data/flyfotos-og-laserscanning/

[7]: https://kortforsyningen.dk/indhold/webservice-liste[
[8]: https://datafordeler.dk/dataoversigt/?emne=landkort%20og%20geografi

[9]: https://osmtools.septima.dk/
[10]:
https://raw.githubusercontent.com/osmlab/editor-layer-index/gh-pages/sources/europe/dk/Geodatastyrelsen-Denmark.geojson

[11]: https://kortforsyningen.dk/indhold/quick-ortofoto-frie-data
[12]: https://sdfekort.dk/spatialmap?layers=theme-gst-orto_foraar_temp
[13]: https://skraafoto.kortforsyningen.dk/

[14]: https://wiki.openstreetmap.org/wiki/AutoAWS