[Talk-us] West Point

Kevin Kenny kevin.b.kenny+osm at gmail.com
Sun Mar 19 00:11:53 UTC 2017


On Sat, Mar 18, 2017 at 12:01 AM, Kevin Kenny <kevin.b.kenny+osm at gmail.com>
wrote:

> But then I realized that West Point is mapped rather peculiarly - rather
> than being a multipolygon with landuse=military, as I'd have expected, it's
> mapped as a city, boundary=administrative, admin_level=8. It is not a city,
> it is a military base, no different from any other. It is large, and
> therefore it extends into three townships. The relevant parcels are part of
> the Towns of Woodbury, Cornwall and Highland. The boundary between Woodbury
> and Highland had been included in the relation for West Point, possibly in
> an effort to make it a city within the Town of Highland?
>
> In any case, I realized that in moving the boundaries of the reservation,
> I was also adjusting township lines. I'm fairly certain that I managed to
> put them back.
>

Committing the sin of following up to my own message:

The West Point polygon came from TIGER 2008, because West Point is a Census
Designated Place. When I discovered that, I refreshed my memory by going
through the painful exercise of reading through all the threads on CDP's
linked from
https://wiki.openstreetmap.org/wiki/United_States_admin_level#cite_ref-35.
New York mappers seem to have reached an overwhelming consensus that CDP's
here are simply for the convenience of the Census Bureau and have
relatively little relationship to facts on the ground. (The situation may
be different in other parts of the country.)

The inaccurate borders are substantially identical to the 2015 file of
CDP's digitized at 1:500,000 scale. At such a small scale, it's no surprise
that borders don't line up!

Even before I started touching the relation, other mappers have made
changes, so I am certain that the relation no longer reflects the CDP. In
the unlikely event that we need the Census Bureau's definition of the
place, the best approach would be to reimport it.

In the meantime, I'm making the unilateral decision to remove the TIGER
tagging and administrative boundary status from the thing, and work on
replacing it wholesale by building it from component ways that represent
the borders from Orange County's GIS. Of course, the boundaries will be
checked against Bing imagery where they appear to follow natural or
cultural features, and conflated with polygons from New York State Office
of Parks, Recreation and Historic Preservation and with existing OSM
features where appropriate.

I'll try to break up and share the ways in the places where the boundaries
of the reservation actually coincide with the boundaries of something else.
These boundaries will be the bank of the Hudson River, and the lines on the
ground where the reservation borders another property that we map, without
a public right of way in between. There are such land borders with at least
three state parks (Bear Mountain, Harriman and Storm King), the Black Rock
Forest, and a golf course in Central Valley. I plan to offset the ways at
highway rights-of-way and at the railroad, as the tax maps generally do.

 The result is bound to be better than the unholy mess that we have there
today. https://flic.kr/p/T1k89u <https://flic.kr/p/T1k89u>
https://flic.kr/p/T1k85m

Last night, I was quite afraid of breaking something, but I've realized
since that anything I'd break is already badly broken. Better just to
forget about the TIGER stuff and get the job done more nearly right.

Thanks to anyone that read this far!
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