[Talk-us] Tagging National Forests

[Christoph Hormann]

On Monday 17 August 2015, Charlotte Wolter wrote:
>          And, Christoph, the forests are divided into subunits
> because that's how they are administered and because many national
> forests are made up of physically separate subunits. They can be as
> much as 100 miles apart. For example, the Apache-Sitgreaves National
> Forest has five such units. If you want information or a permit, you
> have to go to the local subunit. 

I am aware of this, however a national forest with a certain name is 
still one entity that is administered as such by the national forest 
service.  So the national forest as a named feature with proper tags 
indicating a protected area, operator tag etc. should be one entity in 
OSM.  There is nothing wrong with mapping the different subunits on 
their own, but not as a national forest (since they are only parts of a 
national forest).

> So, no, they should not be combined 
> into one multipolygon, because, in reality, they are not a single
> multipolygon. So, while mapping principles are important, so are the
> physical, natural and administrative realities of a place.

The term multipolygon might be confusing here - a multipolygon can have 
multiple separate areas.  This is common for example for archipelagos:

http://www.openstreetmap.org/relation/3705990

but also for national forests in the US:

http://www.openstreetmap.org/relation/335140

When you map it as such programs can better interpret the data like 
Nominatim where you get just one result representing the whole forest:

www.openstreetmap.org/search?query=Dixie%20National%20Forest

instead of a whole bunch of features here:

www.openstreetmap.org/search?query=Apache-Sitgreaves%20National%20Forest

-- 
Christoph Hormann
http://www.imagico.de/