Having read Land_use_and_areas_of_natural_land, I'm still trying to figure out the best approach for multiple land use. The example is where some land is private property, and residential, ie there are houses in the landuse. However, there is also a forest/aka wood occupying the outer bits of of the residential landuse. How to tag this?

asked 21 Nov '12, 19:27

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buzzzy
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edited 22 Nov '12, 10:56

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Pieren
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To follow up, lets assume there is a large "forest", but in it, there are open fields/heaths, bare rock areas. I guess it may depend on the renderer how this is shown, but would one map the forest(wood) as one area, and the heaths in it as individual areas, or would one have to split up the surrounding forest, so the forest(wood) and heaths are not overlapping?alt text

I attach an example, here its the opposite, the forests(woods) are enclosed by open areas.

(21 Nov '12, 22:29) buzzzy

There is nothing wrong per se with overlaping areas (landuse or something else). A residential area can very well include some woodland (many bigger properties do) or a pond in a retail area. If you think an area matches two different OSM tags, then go ahead and map the two.

The debate rages on for cases like a house in a forest : does the forest end where the building begins ? Only if there is a clearing ? How big ? For such nit-picks, use your gut feeling.

Oh, and if a farmer lives on his farm, does that make it a small residential area ? There's only so much micromapping that makes sense. In many cases, it's best to tag the most relevant use of an area and ignore minor ones.

Comming back to landuse=forest (as opposed to natural=wood), remember that it is a close relative to farming (it would have been better to name it landuse=forestry). So if the wood is intended for industrial-scale cutting, the residential area probably stops where the wood begins. If the wood is intended for leisurly walks, good looks, etc, it probably belongs to the residential area.

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answered 21 Nov '12, 20:26

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Vincent de P... ♦
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@Pieren, Vincent, thanks both (I note the difference though :-). I guess the level of detail we put in may be dependent of the imagined use for of the map; a navigation map with all roads, lanes etc right, or a map used for hiking. I guess that in general OSM is perceived more for the first, and indeed nature change more than roads, but also think the map could be very useful in "nature", having smaller details as stones, trail, trees, fences etc included. And in this case, borders between open areas, woods, swampy land are important.

I appreciate the open attitude here in the OSM community, and guess the best approach is not set in stone.

(22 Nov '12, 12:24) buzzzy

Normally, two landuse's shouldn't overlap. If they are, it's either because mappers are too lazzy to create multipolygons relations or it's a lack of values. One exception is the "landuse=cemetery".

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answered 22 Nov '12, 10:55

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Pieren
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There are more exceptions, see landuse=garages, landuse=military, and landuse=village_green. I don't think creating multipolygons for these is helpful in any way.

(22 Nov '12, 12:11) scai ♦

Agree for the exceptions which are imho just bad tags (should be moved to some other key). But residential and forest should not overlap.

(22 Nov '12, 12:17) Pieren

what are bad tags and why?

(22 Nov '12, 12:25) buzzzy

I mean that "cemetery", "military" or "village_green" should not be categorized in the "landuse" key but to something else.

(22 Nov '12, 17:08) Pieren

I'm also convinced that overlapping areas using different landuser values is creating an ambiguity, as it does not clearly mean if the result is the combination of BOTH values, or if one area should exclude the landuse assigned in the other area. Renderers have absolutely no way to determine what to do and the result will be completely random, implementation dependant.

(27 Nov '12, 07:07) Verdy_p

If an area must have two landuses simulteneously in an overlapping region, separate the overlap in a separate multipoligon and assign it a value of landuse with TWO values separated by a semicolon. Renderers will have a difficulty to mix them, but there's no ambiguity of interpretation. If the landuse of one area exludes the landuse from another, suppress the overlap possibly with "inner"/"outer" roles.

(27 Nov '12, 07:08) Verdy_p
showing 5 of 6 show 1 more comments

As i was just pointed to this article for a proof that overlapping landuses are widely accepted i hereby disagree on that.

An area can only have one USE - it may be a used for residential but still be covered by trees.

I consider a layer=* on a landuse be an error and i also consider overlapping landuses an error. When one landuse is completely contained in another landuse thats just a missing multipolygon.

Flo

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answered 14 Jan '16, 17:02

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flohoff
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I agree that layer= on a landuse= seems wrong, but because not all landuse= tags mean "land use" (see http://wiki.openstreetmap.org/wiki/Landuse#problematic_key:landuse_values), I think one could have legitimately overlapping landuse= areas. For more on the fuzzy nature of land use and land cover tagging in OSM, see http://wiki.openstreetmap.org/wiki/Environment

(15 Jan '16, 13:53) neuhausr
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question asked: 21 Nov '12, 19:27

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