landuse=greenfield should not be rendered like landuse=construction

[matkoniecz]

It is not the best idea to render these two in exactly the same way. These two are related but not enough to justify exactly the same rendering.

Heavy color for landuse=construction is a good one, landuse=greenfield may use similar but lighter.

[matthijsmelissen]

See also https://trac.openstreetmap.org/ticket/4142.

[matthijsmelissen]

Could it be rendered as shrub?

[matkoniecz]

It may be anything starting from sand (say, in Egypt) through snow/tundra (Siberia) to shrub/grass/forest (Poland). Rendering shrub will mostly work for my area but in some parts of world the assumption will fail.

[dieterdreist]

Am 20/giu/2014 um 22:29 schrieb Mateusz Konieczny [email protected]:

Not sure. It may be anything starting from sand (say, in Egypt) through snow (Siberia), shrub/grass/forest (Poland). Rendering shrub will mostly work but in some areas it will fail.

wouldn't render it like anything physical, landuse=greenfield is a legal status and there can be virtually everything physical there

[vincentdephily]

wouldn't render it like anything physical, landuse=greenfield is a legal status and there can be virtually everything physical there

+1 I would not render greenfields at all. It's just a nuanced way of saying "land for sale/rent" but there could be anything on it, vegetation- and building-wise. For that matter, it's probably hard to tag a greenfield unless you have access to county council data.

[mverwijmeren]

Greenfield is fairly often very recognizable without any access to official data. E.g. when initial work like new streets in the area is already (partially) done. If the greenfield is former agricultural land, it often lies fallow. Anybody with even a little knowledge about the area will know why.

Please don't stop rendering this just because you don't like the current color.

[matthijsmelissen]

Two examples:

https://maps.google.com/maps?ll=51.582617,4.746094&spn=0.334936,0.617294&cbll=51.582742,4.746756&layer=c&panoid=4DbnKhPzggX8KtPeCJcWiQ&cbp=12,180.79,,0,3.2&t=h&z=11

https://maps.google.com/maps?ll=52.46909,-1.898543&spn=0.002327,0.009645&cbll=52.469091,-1.898545&layer=c&panoid=fH6Apn0LhhaU0_WrNK2nDw&cbp=11,187.65,,0,9.61&t=h&z=17

What would the correct tagging of the second example be?

[matkoniecz]

The problem with landuse=greenfield is similar to highway=proposed. At least in my city there is a massive area of land that is greenfield ("land scheduled for new development where there have been no buildings before") (see maps on https://www.bip.krakow.pl/?dok_id=27732 ). This area will be slowly used for construction within coming decades. In the same way that some marked highway=proposed are planned since early XX century and according to current plans construction will not start within 25 years.

Second link provided by math1985 seems to be either landuse=brownfield (demolished constructions) or landuse=construction (construction already started).

Note that landuse=greenfield currently requires no real changes on the ground, just scheduling area for construction.

[matkoniecz]

https://www.google.pl/maps/@50.0844498,19.8721297,442m/data=!3m1!1e3 - aerial image of something that may be tagged as landuse=greenfield

Everything between http://www.openstreetmap.org/?mlat=50.0841&mlon=19.8775#map=15/50.0841/19.8775 and http://www.openstreetmap.org/?mlat=50.0882&mlon=19.8576#map=15/50.0882/19.8576 is designated to be turned into a residential area.

[matthijsmelissen]

Second link provided by math1985 seems to be either landuse=brownfield (demolished constructions) or landuse=construction (construction already started).

Makes sense, I retagged it now to brownfield.

At least in my city there is a massive area of land that is greenfield ("land scheduled for new development where there have been no buildings before")

Here a similar example in Cambridge:
http://www.openstreetmap.org/#map=15/52.2195/0.0845

I think many areas currently tagged as greenfield should actually be brownfield, or (if work has started) construction. Even preparatory work (e.g. flattening the ground) should be enough for landuse=construction right?

[matkoniecz]

Even preparatory work (e.g. flattening the ground) should be enough for landuse=construction right?

IMHO yes.

This area from Camridge is even worse, it is a proposed greenfield!

[mverwijmeren]

Proposed highways are by definition invisible. Legal greenfield can be invisible, but doesn't have to be.

If something is still actively used for a certain purpose I think you should tag it as what it is used for. "the on the ground rule" remember. If it is recognizable greenfield it should be tagged as such. It doesn't matter how long it stays that way.

If you just run a bulldozer over some terrain and then let it lie fallow for five years I don't think you'll find many people calling that a construction site.

What you are saying now is: I don't like how people have tagged this. If I stop rendering this, the problem goes away. That is not solving anything. It just hides it.

[matkoniecz]

What you are saying now is: I don't like how people have tagged this. If I stop rendering this, the problem goes away. That is not solving anything. It just hides it.

Greenfield tag is simply bad as it bundles "construction is planned and somebody did something on the ground" and "area designated for construction". As word greenfield includes both meaning this tag is a bad tagging scheme and it should be discouraged using all available methods. Not rendering it in the most common style should be quite effective. So except "That is not solving anything." it is an accurate description.

And yes, one of my motivation for this pull request it to discourage usage of what I consider a bad tagging scheme.

If you just run a bulldozer over some terrain and then let it lie fallow for five years I don't think you'll find many people calling that a construction site.

In this case I would probably tag it as landuse=construction and later remove it. I would be happy to further discuss tag for situations like this, but it tagging mailing list may be a better place (though discussion about whatever landuse=greenfield is a bad tagging scheme and/or something that should not be rendered on this map is on topic).

[vincentdephily]

IMHO as soon as construction starts it isn't a gren/brownfield anymore but a construction. If construction stops before anything significant is built, remove the construction tag and add natural=scrub or whatever as appropriate.

I actually don't think that a greenfield is very usefull to map, let alone render. To me it just means "we allow construction projects here", and from a mapping POV it's not usefull until construction actually starts. Why would we map planed construction in a field and not in an already-constructed area ?

In contrast to highway=proposed, a greenfield is very vaguely defined. The local council often doesn't know for sure what proportion of commercial/residential/industrial/etc the brownfield will have. As opposed to a highway=proposed where the council usually has detailed plans long before the construction begins (which might indeed be decades away).

[dieterdreist]

2014-06-25 12:12 GMT+02:00 vincentdephily [email protected]:

IMHO as soon as construction starts it isn't a gren/brownfield anymore but
a construction. If construction stops before anything significant is built,
remove the construction tag and add natural=scrub or whatever as
appropriate.

+1, but not problem to re-add landuse=greenfield as well.

To me it just means "we allow construction projects here", and from a
mapping POV it's not usefull until construction actually starts. Why would
we map planed construction in a field and not in an already-constructed
area ?

we do it the other way round: we map if construction is NOT permitted in an
already constructed (and also in an "empty") area (preservation, protected
area, ...). Anyway, we never map planned construction as landuse, we map
that construction is generally permitted on a green field (regardless
whether it is planned/scheduled or not). Anyway,
landuse=residential/industrial/commercial/retail and landuse=greenfield are
incompatible on the same area.

In contrast to highway=proposed, a greenfield is very vaguely defined. The
local council often doesn't know for sure what proportion of
commercial/residential/industrial/etc the brownfield will have.

how would that matter?

cheers,
Martin

[vincentdephily]

we map if construction is NOT permitted in an already constructed (and also in an "empty") area

Indeed we map "construction not permited" (a blacklist) indirectly with various tags.

Anyway, we never map planned construction as landuse, we map that construction is generally permitted on a green field (regardless whether it is planned/scheduled or not).

Agreed on planned vs permited. But in the previous sentence you said that we maped construction blacklists, and here you say that ww map construction whitelists (aka greenfields). We could do both, but my POV is that we shouldn't bother mapping the whitelist.

Anyway, landuse=residential/industrial/commercial/retail and landuse=greenfield are incompatible in the same area.

They are because it's the same key and because greenfield implies "unconstructed". But if the tagging sheme was "construction=allowed, landuse=residential/meadow" it would work (I am explicitly not recommending that scheme, since it's a generalisation of what landuse=green/brownfield means and I am arguing against mapping that).

how would that matter?

I was explaining why I'm against landuse=greenfield but at the same time for highway=proposed. As mkoniecz noted they are similar, but to me they are different enough that the second one is worthy of rendering. A proposed highway is a much more tangible mappable object, because it is planned (vs allowed) and we know what it is going to be.

[dieterdreist]

Am 25/giu/2014 um 15:19 schrieb vincentdephily [email protected]:

Agreed on planned vs permited. But in the previous sentence you said that we maped construction blacklists, and here you say that ww map construction whitelists (aka greenfields). We could do both, but my POV is that we shouldn't bother mapping the whitelist.

I think this is because we assume in built up areas that you may construct while for other areas the tagging emerges from the idea that per default you can't, hence the greenfield tag

[Matthias84]

I suggest to reintroduce an appropriate rendering of greenfield as it's has same growth like brownfield or construction:

It's also featured at JOSM and ID editors and landcover is an important topic for a map, esp. on lower zoom levels.

[matkoniecz]

Tags are not rendered based on popularity alone. From what I see it was also not removed due to low popularity, but for other reasons.

Has anything changed since it was removed? Or are you disagreeing with reasons for removing it?

[Matthias84]

5 yrs ago the author pointed out, that color style was bad and might not easy to find a good styling for a legal (read: non physical) state. But this is more related to the tag discussion itself but not it's rendering.

I suggest to reintroduce this feature, using a coloring similar to natural=scrub as it is in use and mappers seem to distinguish between a area that is scheduled for construction and ones that are under construction or demolishion.