[Tagging] How to tag: public lands that are accessed by permit?

Kevin Kenny kevin.b.kenny+osm at gmail.com
Tue Jul 19 18:21:53 UTC 2016


In a discussion today on 'imports,' Martin Koppenhoefer raised a
concern that appears to have no answer in current tagging practice. I
suspect that it's yet another case where a fairly common case in the
US violates a hidden cultural assumption in OSM's data model.

The case in question is government-owned lands that are open to the
public but require a permit to access. In a great many cases the
permits are free of charge and granted routinely to all who apply.


In my work, this first came up with an import I did this spring of the
New York City watershed recreation land boundaries. These are not
located in New York City. Rather, they are land in the Catskill
Mountains and in the Croton watershed, purchased by New York City to
protect its water supply from development. Many of these lands require
a permit to access, http://www.openstreetmap.org/way/424230670 is
typical. The permit is obtained simply by filling out a Web form,
submitting it, and printing out the PDF that is sent back, so it's
effectively never denied.

Someone on one of the lists proposed using the little-used
'access=permit' (or in this case, 'foot=permit') to tag this case.
'access=private' feels entirely wrong: it's not 'private land; keep
out', but rather 'there are a few formalities to comply with.' I
stated that agreed with 'access=permit', and the issue passed with
little or no further comment.

A side note: some of the permit-only areas give access only for the
purposes of hunting or fishing, and permit-holders must also hold a
valid sporting license from New York State and be present only in the
season for the game they're pursuing. I chose not to represent that
case in OSM, since the site from which the permit is obtained has


Now I'm working on a separate project - a reimport of the New York
State DEC Lands database. The last import was in 2009 and, in addition
to being out of date, was referenced to the wrong datum (WJS84 vs
NAD27) and had some topological problems (unclosed ways,
self-intersections, even multipolygons with inner ways misidentified
as outer and vice versa). That import has two more places with similar
permission regimes:

(1) The High Peaks Wilderness
http://www.openstreetmap.org/relation/6360488 . There is an extremely
simple permit regime there. Carbon-paper forms are available at the
trailheads if one enters on a trail (as nearly everyone does). You
simply fill one out, sign it, put the top copy in a letterbox on the
kiosk and take the bottom copy with you. Technically, this is required
only in the Eastern High Peaks Zone (east of the ridge that includes
Nye, Street and MacNaughton Mountains), but the boundary is indefinite
and very few hikers ever approach that ridge from the west.

(2) The Long Island DEC nature reserves (except for Ridge Conservation
Area) require a free permit, again obtained for free by filling out a
form on a web site.

I'm fine with 'access=yes' (or 'foot=yes') for the High Peaks; dealing
with the formailities does not require any advance planning on the
part of the traveller.. I proposed 'access=permit' for the Long Island
reserves, and that was when people challenged the idea.


My basic requirement is to discriminate between the three cases:
'private - keep out', 'permission needed' and 'no permission needed'.
I have various commercial trail maps that show the three cases with
distinct rendering. It's very useful in trip planing; "do I need to
remember to bring my NYC access card?" If any two of the three are
tagged alike, they cannot be rendered differently in maps that I

The last couple of times that I raised the argument that "things
tagged alike cannot be rendered differently," several people accused
me of "tagging for the renderer." That rather misses the point. I'm
entirely willing to adapt my rendering to whatever tagging scheme is
settled on. But things tagged alike cannot, even in principle, be
rendered differently, whatever renderer is used.


I favor 'access=permit' since it is succinct and expresses the
intention that a permit is required. 'access=private' does not convey
the idea that permission is routinely granted. 'access=permissive'
does not convey the fact that permission must be obtained. One
alternative that was suggested was 'access=no
foot:conditional=permissive @ permit_holder' - but that tagging is
surely not widely accepted. taginfo.openstreetmap.org turns up only a
handful of uses of 'permit_holder' in any cpntext, and they are not
consistent enough to establish that any of them is following accepted
practice. Moreover, there appears to be a formal syntax for the access
conditions that is incompletely specified. JOSM appears not to like
any specification that I've tried to enter.

Martin points out that this is a better forum than 'talk-us' or
'imports' for raising the issue. Do the people here have any better
idea how to proceed?



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