[Talk-us] Possible [re]import: New York State Department of Environmental Conservation Lands
kkenny2 at nycap.rr.com
Sat Jul 14 06:30:45 BST 2012
In some mapping projects that I've been doing recently, I've wanted
to show the cadastral data for the New York State Forest Preserve.
This immense set of state lands (nearly three million acres, or 1.2
million hectares) comprises by far the largest share of state lands
in the Adirondack and Catskill Parks.
The boundaries of these parcels are publicly available on the
World-Wide Web at
This file - in an earlier version - has been imported once before.
Unfortunately, part of the import appears to have gone awry. A number
of large parcels are simply missing. For instance, a comparison
shows that most of the Indian Head Wilderness is
not in OSM: all that is there is the narrow strip on the east face
of the Catskill Escarpment. Similar missing parcels appear in other
places. I suspect that the root cause is that in one file format
conversion or another, only the first polygon of multipolygon areas
was retained, but it hardly matters.
In any case, the existing import predates the current version of the
file from New York State, so an update may well be in order.
[http://wiki.openstreetmap.org/wiki/Import/Catalogue lists the
import as 'ongoing' - but in fact it has not been repeated.]
Unfortunately, the import also predates the Great License Change, and
In one place, the metadata give:
1. The NYS DEC asks to be credited in derived products.
2. Secondary Distribution of the data is not allowed.
3. Any documentation provided is an integral part of the data set.
Failure to use the documentation in conjunction with the digital data
constitutes misuse of the data.
4. Although every effort has been made to ensure the accuracy of
information, errors may be reflected in the data supplied. The user
must be aware of data conditions and bear responsibility for the
appropriate use of the information with respect to possible errors,
original map scale, collection methodology, currency of data, and other
With that said, there is still hope. I've been in touch with the mapper
who did the original import, and he says that he cleared it with the
relevant agencies at the time. Unfortunately, the email chain of the
negotiation is lost in a system failure. I certainly shall not proceed
until and unless I have clarification that publishing the data in OSM
format according to the terms and conditions of the new license is
acceptable to the issuing agency. Nor shall I do anything while the
license redaction is in progress.
I recognize that imports should be the exception and not the rule,
but this is one case where I suspect an import is mostly harmless.
(1) The import was already done once, and appears to
have added value to the map, despite the problems that I've
identified with the details of how it was done.
(2) Field verification of these data would be inordinately difficult.
To set a typical point on the boundaries accurately would require
hiking in over what is often very forbidding terrain, and attempting
to locate either survey monuments (generally, small cairns of
stones) or surveyors' corner stakes. (Finding the stakes generally
requires a metal detector and a considerable amount of good
fortune.) For instance, note that the contour map illustrated
above shows that the strip of land to the east comprises
a line of cliffs that are some two thousand feet (600 m) high.
We are not talking about mapping the street corners that bound
a city park!
There are - as the metadata notes - ongoing boundary
disputes regarding some of the parcels. These disputes often take
years to resolve, partly because surveys are so difficult to
conduct. (They typically pertain to whether a lumber company
may or may not access certain areas for logging.)
(3) Because of the difficulty of verification, it is highly unlikely
that any mapper has had reason or ability to modify the state's
cadastre, with the possible exception of adding new tags (such
as Wikipedia or other reference links). An automated process that
examines areas tagged with NYDEC_Lands:LANDS_UID can readily
identify whether any tags have been added that were not present
in the original import.
(4) The data in question are of very high quality. They appear to
be the source of the boundary lines in most of the commercially
published large-scale maps of the region in question.
So, what do people think? Is this a project that is worth pursuing?
Does it meet the (justifiably) high bar for pursuing it as an automated
73 de ke9tv/2, Kevin
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