Open Data License/Regional Cuts - Guideline

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Community Guideline - Regional Cuts

Background: What is the problem?

This primarily relates to making and publicly publishing visual 2D maps, (a Produced Work within the terms of our ODbL license), and where the map covers a very large, probably global, area.

If you publish such a map, you may want to make some regions from OpenStreetMap data and some from data provided elsewhere. We will use the phrase "Regional Cut" to define a geographic region that you take from OpenStreetMap. If you can think of a better term, please propose.

The Guideline

Status: Endorsed by the OSMF board 2014-06-06

Read the formal guideline here


Read the formal guideline here

Open Issues, Use Cases, Discussion

Any text here is NOT part of the guideline!

Should there be minimum area limit? How small?

Question to OpenStreetMap community: How big an area? Country-wide or smaller? ... for example cities? Things to consider:

  • City-scale have been "allowed" in the past ... i.e. it has happened but as a community we have never discussed the ramifications. Good, bad?
  • The issue is probably not one of absolute size but of connection between the Regional Cut and the data surrounding it: roads, railways etc. Less is best?
  • What is a reasonable boundary? … countries are well defined admin boundaries … and GIS folks operated all the time on admin boundaries.

Please add your thoughts

I can see that a common use case could be for one regional entity - e.g. a city administration - to want to add a few kilometres of hinterland from OSM. I.e. the main thing on the site is their city map made from their data, but they provide a bit of buffer around the city made from OSM (because they have no own data for that area). This use case does not necessarily require special consideration because it can mostly be served by a "map overlay" technique like we had in CC-BY-SA times. However if we wanted to allow making a combined city+surroundings database without share-alike, then both the "only country size" and the "no holes" rule would have to be adapted. --Frederik Ramm (talk) 18:41, 7 April 2014 (UTC)
1) I consider administrative boundaries only as one of many choices (so current rule "There is a clear boundary around the Regional Cut." is IMHO really fine) and 2) I consider a minimum of "whole country" as conflicting with desired uses. Think of a web site for husky tours in Lapland - there's no project inherent need to contain more than only certain parts of Finland, Sweden and Norway, and there's no inherent need to end at administrative borders (but rather climatic + geologic borders). Think of a project about Arctic & Antarctica - there is no country in this area, so obeying the current rule "The Regional Cut is at least a country." will be quite difficult ;-) Think of a project for big ships - there's no project inherent need to contain _the whole_ countries land masses that contain most of the features, so take up most of the memory, but only for land features nearby the sea. => I don't understand why we need a "minimum size" requirement, but who ever sees a need for it: Can it be formulated relative to the project's scope, e.g. as percentage? --Schoschi (talk) 23:07, 9 June 2014 (UTC)
A reasonable general way to limit the complexity of the cut without referring to minimum sizes, no holes etc. would be to limit how much longer the cut line may be in comparison to a circle of the same area. If you for example allow cuts with a maximum length of two times the circumference of a circle with the same area this would effectively exclude all complex forms independent of their topology and it would be scale independent and would also not require arbitrary rules. --Imagico (talk) 14:46, 19 June 2014 (UTC)

Matching data across map data boundaries

Unless we only allow continents or islands, it is inevitable that there will be a road, a railway or a river that crosses the boundary and does not quite match up. This makes the map look ugly and will make routing fail. Is it reasonable to allow users to adjust the OpenStreetMap data or the "other" data without triggering share alike? If so, are the conditions set in the proposal good enough to prevent users unfairly weaselling out of share-alike?

Please add your thoughts

I like the idea of allowing this but I wonder how we are to check/see if our requirements have been met. --Frederik Ramm (talk) 18:43, 7 April 2014 (UTC)
Assumption of good faith backed up by many eye-balls is the obvious method. To be more sure, we might be more insistent on the map provider identifying what areas they are using and what the boundaries are. This is probably not an issue though unless we are OK with areas smaller than countries ... with a country the border is known and it should be fairly easy to detect which ones. MikeCollinson (talk) 11:08, 10 May 2014 (UTC)
I'd like to allow this too, but I suggest restricting adaptations to the non-osm data, for two reasons: 1) we do not want osm data to be tainted by foreign data (on the other hand, we can/must declare that modifying foreign data in this limited fashion does not taint it with osm data) and 2) we want to discourage adaptation-only changesets that might split ways at the boundary or tweak alignment to the other data instead of to reallity. Vincent De Phily (talk) 09:36, 5 May 2014 (UTC)
Thank you, good point. I have added an extra sentence asking that such adaptions be only made on their local data copies. I think that resolves the issue? MikeCollinson (talk) 11:08, 10 May 2014 (UTC)

Resolution: The concept and text will remain in the formal guideline. The text was slightly modified to point out that these artificial adjustments should not be added back to the main OSM database. MikeCollinson (talk) 05:15, 4 June 2014 (UTC)