Control Point 143

[fourteenthstreet]

I am working on a project with my art students in New York City. We walked up and down 14th st in Manhattan, trying to document and then identify all of the unknown infrastructure items on the street. On the southwest corner of 14th street and 2nd avenue we found an approximately 1.75" circular metal plate with the words "Control Point", the number 143, and a triangle symbol with a dot in the center. We have since learned that this is a geodetic marker, and we are trying to determine function and ownership. the NOAA says it isnt theirs, and we seem to be at a bit of a dead end. and then we found your web site! can anyone out there help? i have an image i can email...

much obliged!

Edited May 20, 2008 by fourteenthstreet

[+TMDMom]

How cool is that?

 

You might find some information HERE

 

If not, there is a separate forum for Benchmark hunting and for Geodetic Surveys, go to the main Groundspeak Forums list, and scroll down. I'm afraid I don't know anything about it, but someone there should be able to help.

 

Good luck!

[+Renegade Knight]

Cities, Counties, States often maitain their own control points. I'd check with public works for the city first.

[+Quiggle]

Moving to Benchmark forum.

[+Kewaneh & Shark]

It's most likely a survey control point for the City. The survey control for most suburban (and some urban) areas usually consists of street centerline and property corner monumentation. In many dense urban areas such as inner city and downtown areas, it's common for the local jurisdiction to place additional or other monumentation to be used as survey control. Many urban areas have 'zero' lot lines, where the buildings are built to, or over, the property line, making it impossible to set a monument on the true property corner, and many areas have streets that are so busy that occupying a centerline monument would be impossible. Downtown New York City would be such an area.

 

The mark may be used for either vertical or horizontal positioning, or both. The triangle stamped onto it indicates that it's at least a monument for horizontal positioning. Its vertical or horizontal position is most likely associated with a local coordinate system and datum, but it may also have associated data from a larger State-wide system (such as State Plane Coordinates) or national system (such as a National Vertical Datum).

 

The number stamped onto the monument would correspond to a plan, or set of plans, on record with the local jurisdiction, most likely the City's Department of Public Works and/or City Surveyor, showing the monument's purpose as well as its location relative to the adjoining properties, rights-of-way, or infrastructure and public improvements, etc.

 

- Kewaneh

Edited May 20, 2008 by Kewaneh & Shark

[+GEO*Trailblazer 1]

 

The blue square with the red dot is where you explained to me.

The closest 2 listed are the one's I sent you the coordinates for.

BM 19 & BM 22.

 

But I still have not found your mark yet.

E-mail me a picture of it.

 

Charles

[fourteenthstreet]

thank you for all of the input! i'm turning the focus local and trying to pinpoint this (via the city and local engineering/surveying companys) as a city owned piece of hardware.

i'll update if i get a conclusive answer.

[fourteenthstreet]

thank you all! here is what will probably be the final word:

 

City engineers involved with City infrastructure design and construction have advised that this is not an official City monument, but a control point established by a private surveyor. Private surveyors tend to keep their benchmarks and control points confidential - hence the lack of an identifying name.

 

it is surprising to me that private surveyors are allowed to just implant the sidewalk with something of their own, but that seems to be the story.