[Talk-us] Potential data source: New York City watershed recreation lands

[Kevin Kenny]

On 05/23/2016 03:20 AM, Frederik Ramm wrote:
> On 05/23/2016 05:35 AM, Kevin Kenny wrote:
>> One-line summary: I want to import the boundaries of New York City
>> watershed recreation areas.
> I've read through your proposal and I would like to know if the
> boundaries you speak of are observable on the ground. I know there won't
> be a line or fence on the ground, but will there at least be signs
> whenever a road or path leads into such an area?
>
> If they are not observable then I am strictly against an import. OSM is
> about mapping things you see (and things others can verify on the
> ground), not importing data from third sources. We do make exceptions to
> that rule, especially in cases were an import can provide a building
> block for future mapper activity - administrative boundaries are such an
> exception. But that does not mean that any and all boundaries that are
> somehow "of interest" can or should be imported.

The areas are indeed posted. Where they adjoin a public highway or
where an established trail enters or leaves, they are marked with
signs.  https://www.flickr.com/photos/ke9tv/14018132286 is a typical
example.

In the back country, they are marked in the same haphazard way that
other survey lines in this part of the world are, but the lines can be
recovered. At least the corners are monumented - generally with cairns
of stones. The more recently surveyed areas also typically have metal
pins beneath the cairns, so that a surveyor with a metal detector
can recover the corner. The lines also usually have paint blazes (or
hatchet cuts, for the oldest parcels) on the trees every few hundred
feet. https://www.flickr.com/photos/ke9tv/17257829216 is a
newly-painted example of a turning point on a surveyor's
line. Recovering the line to survey accuracy would usually require
brush cutting, since there are poor sight lines for a transit. The
line blazes are generally not good enough to use the line as a
'handrail' when orienteering, but make good collecting features to
reassure a hiker that they're following the line and make corrections
to the compass course.

In many cases, the adjacent landowners also post their property lines.
https://www.flickr.com/photos/ke9tv/14037928881 is typical of what
you'll see where a woods road leaves a NYC parcel. Equally many
landowners do not trouble to post - there are too few trespassers to
bother.

There were many mostly-failed attempts to settle the region, so many
lines also can be traced by following 18th-century stone walls -
https://www.flickr.com/photos/ke9tv/13524706704 is an unusually well
preserved example - or 19th-century barbed wire fencing, of which
https://www.flickr.com/photos/ke9tv/17283699335 is again a particularly
well preserved example.

So: In theory, all the lines are observable in the field. In practice,
what you see varies from brand-new posters on the trees to nothing at
all. If you know what to look for, you can find it.

At least all the parcels HAVE been surveyed, which is better than what
you find in the Adirondacks, where even some of the county lines have
never been marked on the ground.

-- 
73 de ke9tv/2, Kevin