DE talk:Gemeindegrenze

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Datenimport in den Niederlanden

Lennard schreibt am 19.6.2009:

Please excuse me for replying in English and to you alone, but in The Netherlands we're now in the process of adding a lot of borders, and I though to share our progress with you. If you want to write something on talk-de about this, that's ok too.
We already had the state (admin_level=2), province (4) and municipality (8) borders from the AND import. We're now in the process of asking each Dutch municipality for their intra-municipality borders, and a lot have already supplied us with GIS-format files, which we can then import into OSM.
Municipalities usually consist of several distinct villages/towns over a larger area. They're called 'woonplaats', and are also what you write on an envelope as a destination place. We're adding these at admin_level=10. They have no self-government, and are just a part of the actual municipality.
There is a large official project for Dutch municipalities to load all their geometries into a national database. This project is called BAG (Basisregistratie voor Adressen en Gebouwen). Part of this is that every council has to pass an official act describing the boundaries.
Because of the Freedom of Information acts (Informationsfreiheit) that we have, we can actually ask for these documents, and even the underlying GIS-format files that are used to create the maps. The best part is, is that 're-use' has been added to the Dutch version of the FOI regulations.
Now for the most relevant part for Germany: I see that several Bundesländer have Informationsfreiheitgesetzgebungen. So try asking them for their official boundary data and permission to reuse this in OSM.
I also map in Belgium, which is in an even worse state than Germany, with respect to boundary data. I've contemplated using the approach you're describing, of building a very course polygon for municipalities and then refining them over time. I decided against it for now, for me personally. The reason being that there are not enough active mappers to make fast progress, and the map would look very strange for too long. Better to have no boundary data than obviously wrong data for months/years.
> Gemeindegrenzen liegen aber für OSM m.W. nicht (oder nur selten) vor.
> Im Wiki gibt es auch keinen Artikel "Gemeindegrenze".
As I said, we're adding them at admin_level=10 in NL.
> Für die Lagegenauigkeit gibt es mehrere Indikatoren:
> 1. amtliche Daten
Ask for this using Informationsfreiheit.
> 2. Grenzsteine (GPS bzw relative Lage)
Can you be sure these are (almost) exactly on the border?
> 3. OSMer mit Ortskenntnissen (mein Haus liegt in XY, oder noch genauer: die Grenze meines Grundstückes ist identisch mit der Gemeindegrenze)
Even local knowledge can be wrong. You really need to find a way to indicate the source of *a part of* the boundary, so you know whether it needs to be revised at a later date. That seems to indicate setting source=* on the nodes.
We're also adding officially imported boundaries with authoritative=yes. That offers no real protection of course, but I hope that in the future, OSM can agree to some different levels of protection of certain data.
Editors could help too. For instance, if you had an option to tell JOSM "Don't let me edit data that's tagged with authoritative=yes", you could on the one hand protect the borders from inadvertent edits by mappers, while on the other hand still giving you the option to work on them by disabling the option.
> 4. OSM-Adressdaten (housenumber, street, postcode, city)
> 5. OSM-"is-in"-Schlüssel
> 6. Luftbilder (Weg, Gewässer, Acker, Waldrand)
Certainly helpful outside built-up areas, depending on how accurate you want to get.
> Und wenn ich jetzt keinen Denkfehler gemacht habe, müssten doch die Gemeindegrenzen in relativ kurzer Zeit eine relativ gute Näherung bekommen?
We're tracking our progress in NL on:
http://woonplaatsgrenzen.openstreetmap.nl/
admin_level
2 red national border
4 blue provinces
8 green municipalities
10 black 'woonplaats'
Areas that have been imported from official sources have a slightly transparent fill. We're still adding those daily.

Andere Länder sind also wesentlich weiter als wir in Deutschland. Ich denke, diese Erfahrungen werden auch für die Zusammenarbeit zwischen OSM und unseren Behörden wegweisend sein. Ich finde Lennard's Bericht ermutigend und die Anregungen hilfreich. Gruss, --Markus 15:04, 19 June 2009 (UTC)

Grenzsteine

auf DE talk:Grenze zeichnen habe ich einen Vorschlag für die Auszeichnung von Grenzsteinen gemacht - nicht jeder Grenzstein ist historisch, nicht jeder historische Grenzstein steht noch auf einer Grenze - deswegen sollte die Position auf einer Grenze eine weitere Auszeichnung erhalten. Gruß -- Schusch 10:03, 31 August 2009 (UTC)