Found, Not Found Or Destroyed

[Papa-Bear-NYC]

Having discussed in another thread a bench mark that was attached to a building that was demolished, here's a related questions.

 

Look at this:

 

 

I found this today. I have seen log entries for similar situations on GC where some have said "found", some have said "not found", and some have said "destroyed". Obviously from a surveyors viewpoint it is no longer useful, so it is effectively destroyed (this one happened to be a vertical control point, and the vertical control line from the disk is lost). Remember the discussion on repairing a benchmark for discussion on this.

 

Of course you can ask "How do I know you found the right location?" Good question. All I can say is the directions were very exact and explicit:

 

SET VERTICALLY IN THE SOUTHEAST FACE OF THE NORTHEAST STONE MASONRY ABUTMENT, 15 1/2 FEET NORTHEAST OF NORTHEAST CURB OF xxx STREET, 7 FEET NORTHEAST OF MAIN SOUTHWEST FACE OF NORTHEAST ABUTMENT AND ABOUT 0.8 FOOT ABOVE THE SIDE WALK.

(I've removed the name of the Street to keep this generic since some of you will know where this is.)

 

Here's a shot of the "SOUTHEAST FACE OF THE NORTHEAST STONE MASONRY ABUTMENT":

 

(click for larger view)

 

You can see the mark (click to enlarge the photo) right where it is described, to as close a degree as one could measure.

 

The GC FAQ says you must find the disk (or feature) and verify the designation, so "found" should be out. What would you log it as?

 

As for NGS, if one of their surveyors recovered this, how would they log it?

 

Thanks

Edited September 29, 2005 by Papa-Bear-NYC

[+seventhings]

I would have, up until now at least, logged the example you've shown as "not found" for both GC and NGS, with appropriate comments attached to both the GC and the NGS reports.

 

However, recent discussions have suggested that the example you've shown could be logged as "found" (but, in extremely poor condition) in both GC and NGS.

 

I have encountered many (well, more than one dozen) of such marks in the past 2.75 years and have logged them all as "not found".

 

It would be a different story, I think, if the horizontal position of the mark in questions was described by adjusted coordinates.

 

W

[+Harry Dolphin]

Hmm... Haven't looked for that one yet, Papa-Bear-NYC. But I hunt on Manhattan, not the other boroughs.

Dang! I thought that we had decided that missing benchmarks, where the stem and original location were obvious, were 'Found in poor condition'? Thusly, I just logged KV0496 as 'found, in poor condition'.

Oh, well. We'll see what Deb has to say, when she gets back from her vacation. (Holograph, expect low stats this month.)

[Papa-Bear-NYC]

I'm puzzled here. The few replies have varied between "not found" and "found, poor condition". Why not "destroyed". It's my impression that a surveyor would never try to survey anything based on a missing disk with a hole in a wall.

 

Humor me for a moment. Consider the following scenario:

 

I'm searching for benchmark XXX and I find it and take a picture of it. While I'm standing there, a worker walks up and says "Excuse me, I'm with the gas company and we're searching for a leak." I step back and he starts digging with power tools, sniffers, etc.. Then oops, his tool knocks the benchmark out of it's setting and breaks it in two. I take another picture, pick up the pieces and send it off to Deb Brown with the pictures and she determines the mark has been destroyed and enters it into the database.

 

A week later Joe is searching for the same mark and finds the hole in the wall. He takes a picture and logs it as "Found, poor condition".

 

THAT MAKES ABSOLUTELY NO SENSE.

 

Where has my thinking gone wrong?

[+Black Dog Trackers]

Good point. It reminds me that I completely forgot about the disk-and-it's-mounting-found-out-of-its-position scenario, since such a scenario is so rare. In such a case, we are to take a picture (or rubbing) of the found disk (a picture of the whole situation would be extremely appreciated) and send this evidence to Deb. This the clearest and most certain type of 'Destroyed'.

[+Black Dog Trackers]

As for scenarios, check this one out.

 

A person manages to convince the NGS that a station is destroyed, but it really isn't.

 

Some survey work is to be done in the area and the mark is considered destroyed, resulting in a bunch of extra money spent either surveying from the next closest mark. Multiply this scenario times X, the number of such potential uses of this mark over time. Even more expensive would involve setting a new station in the 'destroyed' station's stead.

[Papa-Bear-NYC]

Some survey work is to be done in the area and the mark is considered destroyed, resulting in a bunch of extra money spent either surveying from the next closest mark. Multiply this scenario times X, the number of such potential uses of this mark over time. Even more expensive would involve setting a new station in the 'destroyed' station's stead.

BDT: I agree with your point. I think it's perfectly reasonable to mark most of these as "not found, presumed destroyed" with information as to what you found and what the setting was. Then the surveyor could make his/her own decision.

 

My real problem is with logging missing disks as "found, poor condition". "not found, presumed destroyed" is reasonable, if only because the benchmarker might have found the wrong hole in the wall or hole in the rock or other evidence of a missing disk. I just can't see any case where "found, poor condition" is appropriate.

 

If someone fro the surveying community or NGS would say, "Yeah, we would still use that hole-in-the-wall in a pinch" I would consider myself enlightened and change my view.

 

OTOH, as long as you supply complete information in your note when you log the mark, (and assuming the next surveyor reads it), it doesn't much matter how you categorize the recovery.

 

Anyone from NOAA care to comment? Casey?

Edited September 29, 2005 by Papa-Bear-NYC

[GH55]

There is no need to reinvent the wheel here. NGS has provided the definitions already at the Ngs Forum Faq, Frequently Asked Questions:

 

Here are some guidelines used by NGS employees to describe the condition of a mark:

 

GOOD -- Recovered as described on the datasheet; looks healthy and happy.

 

POOR -- Recovered, but shows some alarming evidence of damage or movement. Often the marks can get run over, or frost heaved, or the ground is just too soft to support it. If the mark is scarred and leaning (i.e. the victim of a tractor-lawnmower), thrust up from the ground like a mushroom and/or surrounded by tractor ruts, it's poor. If the disk is gone but some evidence (stem) remains, then it could still be useful; that's a POOR too. Please describe the problem you see in the notes section of the report.

 

NOT FOUND -- I can't find it. Describe how hard you looked or confused you were, e.g., "not found after 10 minute search; unable to recover because all witnesses are destroyed" or "not found; existence doubtful, entire area is now a new shopping mall."

 

DESTROYED -- We prefer the more optimistic "NOT FOUND" unless you have direct first-hand evidence that the mark is completely obliterated. Getting a mark listed as destroyed requires submission of evidence (like a photo) and an e-mail.

 

It is obvious under the foregoing definitions that, to NGS, the mark in your photo is "POOR" and should be reported as such should you decide to submit recovery to NGS.

[evenfall]

If Vertical Control is missing the disc, I cannot use it as Legal or anything else. It is rendered inaccurate. If it does not agree with the datasheet, it is destroyed.

 

Mounts in vertical surfaces no longer show where from which the station is to be measured, so... Now what?

 

Just remember, vertical control must be physically touched to be measured. If added to or taken away is happening, then there is no Match, It must match. If not, then it cannot be used.

 

We think of it as destroyed, but Poor with a note that the disk is missing will tell me I can't use it. an no surveyor ever will again.

 

Rob

[Papa-Bear-NYC]

If Vertical Control is missing the disc, I cannot use it as Legal or anything else. It is rendered inaccurate. If it does not agree with the datasheet, it is destroyed.

 

Mounts in vertical surfaces no longer show where from which the station is to be measured, so... Now what?

 

Just remember, vertical control must be physically touched to be measured. If added to or taken away is happening, then there is no Match, It must match. If not, then it cannot be used.

 

We think of it as destroyed, but Poor with a note that the disk is missing will tell me I can't use it. an no surveyor ever will again.

 

Rob

Thanks Rob. That tells me for vertical control (which this was) it is effectlively destroyed. BTW, I logged the station yesterday as "not found". Here it is: KU0880. It's in Riverside Park, Manhattan. Here's the spec:

KU0880  DESIGNATION -  K 338

KU0880  PID        -  KU0880

KU0880  STATE/COUNTY-  NY/NEW YORK

KU0880  USGS QUAD  -  CENTRAL PARK (1979)

KU0880

KU0880                        *CURRENT SURVEY CONTROL

KU0880  ___________________________________________________________________

KU0880* NAD 83(1986)-  40 47 07.    (N)    073 59 01.    (W)    SCALED

KU0880* NAVD 88    -        11.711  (meters)      38.42  (feet)  ADJUSTED

KU0880  ___________________________________________________________________

KU0880  GEOID HEIGHT-        -31.68  (meters)                    GEOID99

KU0880  DYNAMIC HT  -          11.706 (meters)      38.41  (feet)  COMP

KU0880  MODELED GRAV-    980,248.9  (mgal)                      NAVD 88

KU0880

KU0880  VERT ORDER  -  FIRST    CLASS I

 

The previous quote of the FAQ by GH55 is not quite consistant with this. But the distinction is of concern more to the surveying community than to us as hobbyists.

 

Many of us may not check whether a mark is vertical, horizontal or what, so the bottom line for us, if we are to be of help to the NGS and surveyors, is to provide complete and accurate information in the notes section.