Re: [Talk-us] West Point (Kevin Kenny)

[OSM Volunteer stevea]

On Mar 19, 2017, at 5:00 AM, Kevin Kenny  via talk-us-requ...@openstreetmap.org wrote:Thanks to anyone that read this far!Oh, I'm reading, all right!  Kevin, please don't sweat too much more the seriously yeoman work you've done to clean up an "unholy mess."I do recall recently reading over that admin_level page (tap, tap, tap myself) and seeing "There is some degree of support for removing the least relevant CDPs from the database, but note that CDPs are relevant in some parts of the country, such as Alaska."Breathe.  Feel good about OSM and West Point and CDPs and everything you've painstakingly done.  It's all good.  And thanks for your updates here!SteveACalifornia
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Re: [Talk-us] West Point

[Kevin Kenny]

On Sat, Mar 18, 2017 at 12:01 AM, Kevin Kenny 
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/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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[Talk-us] West Point

[Kevin Kenny]

I have some questions about US Military Academy - West Point.

I was resolving a map note
http://www.openstreetmap.org/note/929376#map=14/41.3276/-74.1002&layers=N ,
where the user queried a fence and gate signed, "US GOVERNMENT PROPERTY."
Looking at the map, and with personal knowledge of the area, I realized
that the boundaries of the US Military Academy (West Point) were cut off
incorrectly at the boundary of the Town of Woodbury.

Since the tax rolls for the town are released to the public domain, I also
knew that I had the data to repair the boundary of the Academy, and I did
so (correcting parcel alignments with respect to Bing where they were
obviously supposed to follow natural features or roads). I uploaded that,
and there the map stands.

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.

In addition, there are a few more issues with West Point.

The legal boundary of the reservation does not encompass the rights-of-way
of New York State Route 293, Mine Road between 293 and Fort Montgomery, and
possibly a couple of lesser ways, although these would need a field check -
I suspect they come from a failed conflation in the tax maps.

It's also pretty badly mapped all around its border, apparently as it came
in from TIGER. There are a lot of places where it misaligns with Harriman
and Storm King State Parks, with the highway grid and with the features
visible on Bing. There's quite good concurrence between the highway grid as
mapped in OSM, the aerial imagery, and the property lines from New York
State Office of Parks, Recreation and Historic Preservation. West Point's
boundary from TIGER is the odd man out.

I'm a little nervous about proceeding, not wanting to break boundary
relations, but it seems to me that West Point should not be
boundary=administrative, and its relation should not be type=boundary.
Instead, I think it should be a multipolygon, landuse=military, and have
the mess of TIGER and is_in tags simply removed.

Also, "The Plain" parade ground should simply be a point of interest, not
part of the relation.

I'm sorely tempted simply to rebuild the multipolygon from the tax data,
conflating its shared boundaries with those of the rivers and of the
adjoining state parks and golf courses as they already appear on OSM, and
inspecting it manually against Bing where it appears to follow natural and
human geographic features. Would it give anyone a horrible case of
heartburn if I were to do this? Or is this simply tidying up yet another
one of TIGER's messes?

Thanks

Kevin
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