[Talk-us] Tagging National Forests

[Kevin Kenny]

On 08/19/2015 05:29 AM, Nathan Mixter wrote:
> In any discussions about land use and land cover, we should look at 
> what organizations have done and how they have mapped ares. For 
> instance, in USGS imagery in JOSM you can see how they render borders 
> with just a dashed line and let the land cover have various shades of 
> color on top of it.
>
> The U.S. Forest Service has a distinct classification for mapping 
> vegetation within the forest. And the USDA differentiates between use 
> of forest land and forest cover 
> (http://www.ers.usda.gov/data-products/major-land-uses/glossary.aspx).
>
> Here is how the USGS defines land use and land cover 
> (http://www.mrlc.gov/nlcd92_leg.php and in more depth at 
> http://landcover.usgs.gov/pdf/anderson.pdf). Not sure how other 
> countries map land use and land cover, but this is a sample from what 
> the U.S. does.
>
> >From 
> http://www.ers.usda.gov/about-ers/strengthening-statistics-through-the-interagency-council-on-agricultural-rural-statistics/land-use-and-land-cover-estimates-for-the-united-states.aspx#h
> "Land use and land cover are often related, but they have different 
> meanings. Land use involves an element of human activity and reflects 
> human decisions about how land will be used. Land cover refers to the 
> vegetative characteristics or manmade constructions on the land’s 
> surface."

I hear a lot of argument here, and much of it is philosophizing. Let me 
offer another argument. Deficiencies in the standard rendering are 
leading us to impose constraints that do not exist. The very idea that 
we should have to cut out watercourses and highways from a National 
Forest to show it correctly on a map is absurd. If the renderer cannot 
cope with the idea that the Elm Ridge Wild Forest (a protected area - 
and specifically an area of state ownership with public access for 
recreation and harvesting of fish and game) lies partly within and 
partly outside the Catskill Park (a different sort of protected area, 
not all under state ownership) and in turn has several bicycle corridors 
(an area of less protection) overlaid upon it, then it cannot cope with 
the messy reality that I work with locally.

Since I render my own maps, let me begin by observing: THE LACK OF 
CONSENSUS ON THESE ISSUES MEANS THAT I DO NOT USE OSM AS A DATA SOURCE 
FOR PROTECTED AREA BOUNDARIES. I go to alternative, mostly government, 
data sources for the boundaries of government and other protected lands 
and use them for map production. I simply cannot cope with wholesale 
retagging of these areas every few months as each new tagging scheme 
comes through. WE NEED TO REACH SOME SORT OF STABLE CONSENSUS, at least 
one that lets us produce medium-scale maps suitable for general use 
without running on a hamster wheel of patching renderers to adapt to 
changing tag schemes.

I've half come around to the position that National Forest boundaries 
don't belong in our database at all. They're often not any more 
observable on the ground than any other property lines - and I believe 
that we reached a consensus that delineating land ownership is outside 
the scope of OSM. (Am I wrong about this?) In fact, the reason that I'm 
able to ignore OSM on the point is that most of the data I need is 
available in authoritative form from the agencies that manage the land.

Unfortunately, some of the smaller agencies (mostly county and municipal 
agencies) still haven't moved forward into using GIS, or simply don't 
have the resources to make what GIS data they have available to the 
public, so there's still some amount of measuring on paper maps. I'd 
done a few local nature preserves that way (along with cross checking by 
hiking to corners and collecting GPS waypoints), and it had been 
convenient to use OSM as a store for the data so collected, but I'm 
willing to give that up and go back to holding the data privately and 
rendering them as another layer - doing an export from OSM to my own 
data store. Again, the features are hard to observe in the field. It's 
quite an interesting hunting expedition, trying to find the corners of a 
county nature preserve where the adjoining landowner doesn't trouble to 
post the land. Sometimes it involves trying to locate survey pins with a 
metal detector in dense forest.

Since we don't have a good general policy for OSM maintenance of data 
where the authoritative copy is elsewhere, OSM really simply becomes the 
convenience of "one stop shopping." I enjoy having that convenience, and 
so do many other users. But for some of the data, it simply costs too 
much time and effort to negotiate the minefield of tag wars.

And I still claim it's largely because of the renderer.

So now let me move forward to specific rendering suggestions - noting 
that that I'm here as a field mapper (I mostly do hiking trails and 
associated facilities, and for the most part don't armchair-map 
anything), a consumer of OSM data (I produce my own maps for my 
GPS-equipped smartphone, because I find them more useful than anything I 
can buy), and a Mapnik user (I have my own Mapnik scripts. What the 
Standard renderer does is of little consequence to me.) I still think my 
approach to the general problem of rendering the competing ideas of land 
use, land cover, and land administration may be useful.

Refer, if you will, to 
http://kbk.is-a-geek.net/catskills/karl.html?la=42.3024&lo=-74.1807&z=13 
This is a fairly conventional "topo map" rendering in a style intended 
to be of use to hikers navigating using a GPS unit.

There are numerous administrative units, some overlapping, shown here. 
The most significant is the Catskill Park. This unit is truly one of a 
kind - it is enshrined in New York State's constitution, and takes a 
constitutional amendment to change it. It does not reflect land 
ownership or land use but merely land administration: the Department of 
Environmental Conservation serves as a "super zoning board."  You can 
see, for instance, to the west, that the village of Windham with its 
extensive ski resort is located entirely within the boundaries of the 
Catskill Park. Rendering this boundary in blue defies all topographic 
map convention, but is a longstanding tradition in New York. Anyone 
living in the Park knows the significance of the Blue Line.

To the east, you'll see at least two different protected areas, the Elm 
Ridge Wild Forest and the Windham-Blackhead Range Wilderness. Wild 
Forest is a lower level of protection than Wilderness, and allows such 
uses as mountain biking. Showing these parcels separately is essential 
to a mountain bike user, since it will indicate how far s/he can legally 
ride on the trails. Note that the Elm Ridge Wild Forest extends outside 
the Blue Line at the north. The area outside enjoys protection as a Wild 
Forest, but does not enjoy the protection of the Catskill Park. The 
state is free to classify the land as other than Wild Forest, sell it, 
or develop it by a simple act of the legislature, a much lower hurdle 
than amending the constitution.

You'll see how the parcels can be shown readily by using a 
semitransparent shading on the interior edge of the polygon, without 
obscuring what lies within.

Shown in the base color is land cover with deciduous forest (medium 
green) predominant. At the highest elevations and in the wet low-lying 
areas, coniferous forest (dark green) takes over. There are some patches 
of mixed forest (lightest green) along with farmland (buff), marshland 
(aqua) and developed land (pink) in the valleys. Some of the cliffs have 
patches of bare rock and scree (grey). A light hill shading overlays the 
whole.

So here we have large administrative units (lines with their names shown 
on the interior), smaller and sometimes overlapping administrative units 
and land use designations (lighter lines with transparent color overlay 
on the interior, with names in the interior for the larger areas where 
possible), hill shading, and land cover (base color) all shown. The 
visual clutter can get pretty bad in spots, particularly where different 
agencies' GIS systems fail to agree, but the information density is high.

Patterned overlays are also still available, and I'm not using them very 
much yet. You can see that I mark emergent wetlands (from yet another 
data source) with a pattern, if you use the mouse wheel or zoom buttons 
in the map that I linked to to examine the wet area north of Hensonville 
at the center. Showing these without a rendered boundary seemed 
appropriate, since they're approximate at best (and depend on rainfall 
and beaver activity in any given year).

I contend that if the standard rendering made more use of edge in-fill, 
pattern fill, and transparent overlays, we'd have fewer arguments. With 
our use of solid color fills (and opaque pattern fills) exclusively, we 
simply don't have enough ways of displaying the competing concerns, and 
lurch among tagging that focuses on land ownership, land administration, 
land use, and land cover - all related, but distinct concerns - with 
cascading effects downstream as people try to render whatever tag scheme 
has come out of the latest round of a never-ending argument. In large 
measure, it comes down to the renderer. We try to have a tag scheme that 
says, "this parcel is inside the Catskill Park. It's owned by the 
Department of Environmental Conservation. It's open to the public. It's 
covered with balsam forest. It's managed as Wilderness Area" in a single 
statement. That simply will never be successful. Renderers will have to 
deal with these cross-cutting concerns, which means rendering 
overlapping areas that have different meanings.

We might as well face the fact that these issues are chaotic, they're 
always going to be chaotic, and no tag scheme will ever describe them 
fully. But please, can we try at least not to have continual breakage 
for major, signed features such as National Forests or the Catskill Park 
that nearly all map users will want to have rendered somehow?

-- 
73 de ke9tv/2, Kevin