Jump to content
Sign in to follow this  
Followers 1
inagaddadavida

Found 'destroyed' benchmark

Recommended Posts

I'm not much of a benchmark hunter, but I stumbled onto one in Chapel Hill, NC last weekend and decided it might be a good idea to log it. It's PID is: EZ2860. There is a log from 1975 that indicates it was destroyed, however I found it in great condition and took photos.

 

Reading the FAQ about logging these things with the NGS makes me a bit nervous about logging one that is supposedly destroyed.

 

Not sure if there are any benchmark experts here, but does anyone have thoughts on this?

Share this post


Link to post

Welcome to the Benchmark Hunting Forums!

 

What you found is called a traverse station.

It has a latitude and longitude that has been carefully measured to meet NGS standards.

If moved or tilted, the mark completely loses it's value.

 

But there's actually two marks. One set at ground level and a subsurface mark.

The subsurface mark exists in case the ground level mark has been compromised.

 

So, is the station destroyed as reported in 1975?

Not really - a new disk can be reset at ground level, (provided the underground mark has not been disturbed).

 

From your photo of the surrounding area, I can see that the concrete pillar is substantially higher than

originally described as being 2 inches above ground level and appears to be loosely stuck back in the hole.

 

I'd log the station as 'found' on the geocaching website, since the disk is very close to where it should be.

However, I'd log it with the NGS describing the concrete pillar being set in an upright position with the top

protruding about one foot above ground level, showing some damage possibly caused by road construction.

 

Hope that isn't too confusing... and good photos by the way!

~ Mitch ~

Edited by Difficult Run

Share this post


Link to post

Ok, thanks for the info Difficult Run.

 

So I'm guessing that this would qualify as being in 'poor' condition since it doesn't exactly match the original description of a 2 inch protrusion, correct?

Share this post


Link to post

Here's another marker that appears to be completely normal but which is actually destroyed: PE0283.

 

If you read the original description, you'll see this was a disk set on a granite park bench in Bar Harbor, Maine. If you were to go to Bar Harbor and poke around the water front, chances are you'll find the bench and there you'll find the disk, good as new. So what's the problem? The problem is in 2005 they remodeled the park and removed the bench from where it was and when the project was finished, they put the bench back in a different place.

 

Once they moved the mark, it's use as a surveyors mark was destroyed. In other words they may as well have thrown that disk away. The contractor probably thought they were doing a favor when (if) they noticed the disk. Maybe they said "Hey this looks like one of those surveyor's thingies, let's make sure we put it back some where".

 

This brings up the point "What is a bench mark". It turns out to a surveyor (and to the NGS) a bench mark is a disk (or some other mark) which is at a precise location or precise elevation and has been measured to a high degree accuracy and standards.

 

So what did the 10 Geocaches who logged this as "found" since 2005, actually find? They didn't find station PE0283, they found the disk which used to mark the station PE0283. Station PE0283 was actually officially marked as destroyed by the NGS (and logged as such in 2005 by Zhanna - see the NGS Data sheet).

 

Since that's a bit complicated to explain, I mostly don't bother in these cases to try to convince any one that they actually didn't find the mark. In fact if I didn't know the history, I might also have been fooled into thinking I had found it.

 

You have evidently encountered a very similar case.

Share this post


Link to post

So I'm guessing that this would qualify as being in 'poor' condition since it doesn't exactly match the original description of a 2 inch protrusion, correct?

Technically, since the surface mark was noted in 1975 as being out of position, the surface

mark is still regarded 'destroyed'. Now, the condition of the subsurface mark would still

be considered being in good condition unless there is a reason found to the contrary.

 

As Papa-Bear-NYC said:

It's really not the disk that the NGS or a surveyor is concerned about, but the point in space that

it represents. A surveying professional would probably view this station as 'poor', since that

'point' could be re-established with a reasonable degree of certainty, with some difficulty.

 

On the geocaching website, I'd personally report the disk with a 'note' instead of 'found', explaining

that it is apparent the concrete pillar was returned fairly close to it's original position, but not exactly.

Most geocachers would still qualify your mark as being 'found', since they see the disk in a proper setting.

So log your find as you see fit.

 

Sorry for all of the doublespeak. Folks on this forum take benchmarking pretty dang seriously. :o

 

Glad you're asking these questions as it shows your keen interest in benchmarking!

~ Mitch ~

Share this post


Link to post

That local engineer should have removed it from the scene or broken up the concrete and removed the disk.

 

This is destroyed, no good for anything. Close is never any good in Surveying.

Edited by Z15

Share this post


Link to post

Welcome to the Benchmark Hunting Forums!

 

But there's actually two marks. One set at ground level and a subsurface mark.

The subsurface mark exists in case the ground level mark has been compromised.

 

So, is the station destroyed as reported in 1975?

Not really - a new disk can be reset at ground level, (provided the underground mark has not been disturbed).

 

~ Mitch ~

Mitch,

 

What makes you think that there are two marks at this location. There is no information to indicate that there were any reference monuments or sub-suface marks installed with this station, a sub-surface mark may have been the norm with the USC&GS, but not with all other agencies.

 

Also, the 1975 recovery report must not have had any photos or positive identification for this station actually being destroyed, because this station is still in the active NGS data base and not in a destroyed status.

 

As far as geocaching goes, this is a find; without survey verification you have a solid, positively identified mark at this location.

 

Now as a surveyor, when I read the last recovery I am going to either verify before I accept this mark or I am going to avoid it altogether.

 

CallawayMT

Share this post


Link to post
Also, the 1975 recovery report must not have had any photos or positive identification for this station actually being destroyed, because this station is still in the active NGS data base and not in a destroyed status.

 

Back in 1975 all you did was fill out a postage paid card and mailed it to NGS. You had to send them the survey disk for it to be labeled as destroyed. We would send the ones we found to the mark maintenance person or contact him and he would travel up here and take car of it when he had enough to make the trip worth while, he was located in another state.

 

All they did was include a photo copy of the sent in card in the records.

Edited by Z15

Share this post


Link to post

Not meaning to rain on this parade (again) but there is no documentation that there ever was an underground mark. Since this was a traverse station, not a triangulation station, I would not assume that there was an underground mark. In my area there seldom is (for tri-stations) for various reasons. In other cases I have seen documentation that they were established. Notice that there were no reference marks set either, so standards for tri-stations were clearly not followed. I have no idea what the standards for a traverse station were. The only one I have found had no reference marks and no underground mark. The only way to know for sure would be to dig up the original field notes, which may or may not exist.

 

In the absence of such a mark, there is no recovering this station. Dead is dead. As Z15 says, close counts for nothing. As McCoy said to Kirk "He's dead Jim". :blink:

Share this post


Link to post
Mitch,

 

What makes you think that there are two marks at this location. There is no information to indicate that there were any reference monuments or sub-suface marks installed with this station, a sub-surface mark may have been the norm with the USC&GS, but not with all other agencies.

 

Also, the 1975 recovery report must not have had any photos or positive identification for this station actually being destroyed, because this station is still in the active NGS data base and not in a destroyed status.

 

As far as geocaching goes, this is a find; without survey verification you have a solid, positively identified mark at this location.

 

Now as a surveyor, when I read the last recovery I am going to either verify before I accept this mark or I am going to avoid it altogether.

 

CallawayMT

Hi Callaway,

 

Your point is well taken. I'd be curious to find out if a subsurface mark is required to meet NGS standards.

Perhaps DaveD will weigh in on this one.

 

So to answer your question:

Since the station was still in the NGS database after being reported destroyed by a local surveyor,

I was assuming it still had an underground mark associated with it, as most horizontal marks do.

According to the datasheet, there are two pine trees with 3 lead nails imbedded in each,

both about 12 feet away and serving as reference marks, (not sure how reliable that is).

You're correct about the omission of an underground mark description.

 

Given that there is damage to the concrete pillar, the mark being in a substantially higher position than

what was originally monumented and the 1975 recovery report, I'd conclude mark has been disturbed.

 

So this begs the real question:

Does the station have an subsurface mark?

 

~ Mitch ~

Share this post


Link to post

Do any stations other than triangulation stations have an underground mark? My experience is limited, but I do not recall hearing of any. I've run across many that do not, but that is a different story.

There are any number of stations that are obviously destroyed, but still in the NGS data sheets. Even a number, like the one cited by OP, with destruction attested to by a LOCSUR. Not to mention the number of bridges completely rebuilt; dams destroyed, pipelines built on the east side of Clinton Road... I'd guess that it depends on the personnel, and the requirements at the time.

I find amusing, for instance, resets set next to the stem of the original station. KV0131 No one thought to tell NGS that the original had been destroyed, when they set the reset?

Such is life, and all part of the game.

Edited by Harry Dolphin

Share this post


Link to post

Looking at the pic of the mark I am pretty sure it is one of the precast marks that were popular in the 1930s and 1940s. I thought they had stopped using them by the time that one was set though. These posts are very thin and easy to break. Chances are the broken post was put back in the hole it used to be in, or even into a new hole. No matter--it is unusable. I have found a number of these marks broken, and one was even set back on top of the bottom piece from where it had snapped and looked fine. It was only because I tried to clean the disk and the post wobbled that I discovered it was broken.

 

As for underground mark, I would bet a lot against it. Like others mentioned, just being a traverse station (and therefore having adjusted horizontal coordinates) doesn't automatically mean it would have an underground mark. I am pretty certain the description would mention an underground mark if one existed (but of course that is no guarantee that it happened).

Share this post


Link to post

Underground marks were the norm at Triangulation Stations (from before 1912 to the end of triangulation in the early 1980's), however I wasn't sure about Traverse Stations. So, I referred to USC&GS Special Publication #137, "Manual of First-Order Traverse" from 1927 available on-line at: http://docs.lib.noaa.gov/rescue/cgs_specpu...35no1371927.pdf

 

The first quote below is from pp10-11 and the second from pp12-13. If an Underground Mark and/or Reference Marks were set they should have been mentioned in the station's description. Note, much more information is included in SP#137.

 

"A standard station-mark tablet, set in a mass of concrete at least

10 inches in diameter and accurately centered under the surface

mark, should always be established for an underground mark where

soil conditions permit. The tablet should be stamped with the same

designation as the tablet in the surface mark."

 

"Reference marks should be established only in special cases. They

should be used when the station mark is entirely beneath the surface

of the ground and there are no permanent witness marks near it. such

as road crossings, etc. Reference marks should be set if the station

is at a railroad crossing or junction point or if both of the adjacent

stations are 4 or 5 miles distant. In cases where reference marks

are required, two should invariably be established for each station."

 

GeorgeL

NGS

Share this post


Link to post

"Reading the FAQ about logging these things with the NGS makes me a bit nervous about logging one that is supposedly destroyed."

 

EZ2860 is an interesting find, and it could be significant in the near future, since a lot of new development is planned for the area of the Airport in Chapel Hill.

 

The Local Surveyor who filed the report in 1975 might have been in error. I doubt that anybody took the time to re-erect this monument. They are very heavy, and it involves digging a DEEP hole!

 

I checked the NCGS website for updates on DUMP, but there is nothing since the 1975 report.

 

This would not be a good disk for your first submission to NGS. Because you were not expecting to find it, you did not know in advance about the 1975 report. What is needed is for someone to visit the site and compare the original description with what exists, today. An alternative would be to search the history of the tax parcel on which it is located. Unfortunately, the Orange County (NC) GIS website is undergoing a major overhall, and I was not able to access it, this morning.

 

My recommendation is to let your GEOCACHING log stand as written--and I'll echo the compliments about the good photographs. But don't log anything with NGS. More info about this station will come to light in the future--either as history becomes available, or as surveyors evaluate the station for possible use when development begins.

 

I live nearby, and perhaps I can get out there to take a look. Did you go in via Municipal Drive, or did you access the site from the airport, itself?

 

Best regards,

-Paul-

Cary, NC

Share this post


Link to post

 

I live nearby, and perhaps I can get out there to take a look. Did you go in via Municipal Drive, or did you access the site from the airport, itself?

 

Thanks all for the comments. I'm going to leave the geocaching log but not report it to the NGS since I obviously don't have enough experience with these things.

 

PFF, I was doing the "plane spotting" series of caches around the airport, so I was basically just skirting the fence all the way around counterclockwise as much as I could. If you look at the satellite view on google maps I actually came right through that lot with all the trailers. I would think that coming down Municipal Drive ought to work though.

 

I'll be interested to hear what you have to say about the mark.

 

I actually don't even recall touching the post to see whether or not it was secure, will have to remember to do that in the future.

Share this post


Link to post

Thanks for the info. I'll send you some follow-up details, after I have a chance to check it out in person. It might be a couple of weeks, but I'll get there, eventually. There are a number of benchmarks in the immediate vicinity, so it would make an excellent project for a few hours of hobby time!

 

I probably can enlist another local BM hunter to assist. (Kyle, are you up for another challenge?--Grin.)

 

-Paul-

Share this post


Link to post

Thanks for the info. I'll send you some follow-up details, after I have a chance to check it out in person. It might be a couple of weeks, but I'll get there, eventually. There are a number of benchmarks in the immediate vicinity, so it would make an excellent project for a few hours of hobby time!

 

I probably can enlist another local BM hunter to assist. (Kyle, are you up for another challenge?--Grin.)

 

-Paul-

This sounds like an interesting one. There are a few others around the area that I'd like to visit also, such as EZ2789 I haven't been out on a big hunt for awhile, so I'd really enjoy starting back up again with these. Paul, send me an e-mail about times your schedule will allow you and maybe we can work something out!

Share this post


Link to post

My wife and I drove over to "DUMP" (EZ2860), this morning. I wanted to take a GPS reading and see the disk for myself. I took a few photos and measurements which I am going to forward to NCGS on Monday. I'll be asking them to check their records to see if they reset the disk but did not update the NGS database.

 

Here are my observations: The GPS reading was exact, when averaged over a 2-minute period, and the elevation was about right. I did not see any aluminum reference tags on nearby trees, which means that it probably was not reset by NCGS. They usually nail their triangle-shaped tags on nearby trees, and they would have updated their office's on-line database (which did not happen).

 

My theories: The 1975 "destroyed" report may have been an error. There is another benchmark (EZ2797) 200 feet to the east which was destroyed during construction of a cement parking pad. Perhaps that's what the surveyor found. Or, perhaps DUMP really was pulled out of the ground and someone who is not a surveyor replaced the mark in the approximate location where it once stood.

 

For now, that's all we know. Hopefully, I can uncover additional info, in which case I'll post an update.

 

-Paul-

 

(Edited to insert links.)

Edited by PFF

Share this post


Link to post

>around the airport, so I was basically just skirting the fence

 

Sounds like a way to get arrested.

Share this post


Link to post

Lost02 asks:

 

Paul - did you check to see if the monument felt stable?

 

Yes. It was "rock steady". However, it projects 1.2 feet above ground, which is considerably different from the original description. The monument is at the side of a recently-constructed gravel road, and the top may have become more exposed as the area was graded. There is a deep ditch on one side. Original position or not, it will be in danger of being struck by a vehicle, or eroded on one side.

 

 

Bill93 picked up on the finder's description of "skirting the fence" at the airport, and commented:

 

Sounds like a way to get arrested.

 

An excellent reminder! In this situation, we are dealing with a small, private airport operated by the University of North Carolina. Nevertheless, it is a real airport. Fortunately, this benchmark and the nearby cache series are well-removed from the air center. The University owns hundreds of acres, and the airfield is only a small portion of it. The remainder of the land is wooded, and is available to the public for jogging and walking. It also is parallel to the runway, so there are no overflights.

 

This is not true of the average airport. Being "in the nearby woods" can get you in hot water very quickly! An airport authority will post signs indicating areas where you are not welcome. Always heed them!

 

-Paul-

Edited by PFF

Share this post


Link to post

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

Loading...
Sign in to follow this  
Followers 1

×
×
  • Create New...