[Tagging] landcover=trees definition

Friedrich Volkmann bsd at volki.at
Mon Aug 17 16:50:33 UTC 2015


On 17.08.2015 00:29, John Willis wrote:
> This is the crux of the landcover argument. 
> 
> Because landuse=* implies what the land is used for - therefore man-altered and decided usefulness.  natural=* was then interpreted by taggers to be the opposite - the "natural" state of the land which was heavily influenced by the landuse=forest /natural=wood debacle. 
> 
> Landcover=* just says "this is here" , without adding implications as to its use or origin.

I know what you mean, but you are missing the point that landcover is
layered. "This his here" applies to bedrock, ground water, soil, surface
water, vegetation (root layer, moss layer, herb layer, shrubs layer, tree
layer), and air. So we need multiple keys to specify them all. Or we just
consider one of these layers, but this needs to be clearly defined.

We already have tags for certain layers, such as surface=*. Unfortunately,
that key is spoiled by surface=grass which means another layer. This would
better go to a vegetation related tag. The most common tag for vegetation is
natural=* - which in turn is even less clean because it covers surface,
water and landforms as well.

Let's not make the same mistake again with landcover=*.

One solution could be a landcover:* scheme instead of a single key. Say,
landcover:surface=* for earth/sand/mud/rock/concrete/asphalt/etc. Then some
vegetation tags:
landcover:vegetation:moss=yes/no/percentage
landcover:vegetation:herbs=yes/no/percentage
landcover:vegetation:herbs=yes/no/percentage
landcover:vegetation:shrubs:=yes/no/percentage
landcover:vegetation:trees=yes/no/percentage
(with percentage = 100 * covered area / total area, so the sum of the
percentages possibly exceeds 100)

as well as
landcover:vegetation:herbs:height=0.2
landcover:vegetation:shrubs:height=1.5
landcover:vegetation:trees:height=10

This would enable nice 3D rendering.

> This also would allow for some man-made landcovers; as several times i am dealing with a place where concrete or asphalt is covering the ground, but not as road or path or building. This is a weaker use case, but it would be nice to say "here is 2000sqm of concrete. It is the remnant of an old airport. The airport is gone, it is not a road, a building or a structure. It is now a (currently) purposeless expanse of concrete. Currently I have to map it as the negative space surrounded by other things (meadow) to leave the impression something is there (NAS Alameda in San Francisco is a perfect example: https://www.google.com/maps/@37.7813303,-122.3170894,16z/data=!3m1!1e3 part of it is now roads, tracks, or other facilities, but it is an abandoned airport where most of the feature has no use nor is natural).

We can map the area of a highway as either highway=xxx + area=yes, or
area:highway=xxx. If it is no more in use, we can add disused=yes or
abandoned=yes. We can use a similar approach for abandoned airports. I've
also seen some abandoned primary highways tagged as highway=track, because
they can still be used as tracks. This would also work for abandoned airport
runways. All in all, we've got plenty of possibilities.

Of course, if you just want to store the information that there is an area
sealed with a layer of concrete, some simple surface=concrete would be more
to the point.

> Grass along the sides of manicured roads (like on a cutting or separation for safety or noise control), which are part of the roadway's land, but not part of the road - nearby residential houses, but not part of a residence nor used as a park - its there just to be grass. 

We've got landuse=grass for that.

> Landcover=iceplant would be brilliant for southern California freeway mapping.
> 
> Its not used for anything other than being "iceplant"- occasionally a car will go in it, but it's job os just to be "there" so the ground isn't dirt or dead meadow grass. Sounds like a landcover to me.

Or landuse=flowerbed and possibly species=Mesembryanthemum crystallinum.

> If I had landcover=trees with a boundary  line like nature reserve, I wouldn't have to decide between wood and forest, when it is a bit of both.

I agree that the forest/wood distinction causes headaches, yet both are more
than just a cluster of trees. I wouldn't oppose landcover=* as much if the
suggested tag für forests/woods were landcover=wood.

-- 
Friedrich K. Volkmann       http://www.volki.at/
Adr.: Davidgasse 76-80/14/10, 1100 Wien, Austria



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