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I went looking for my first benchmark today and found that the area is now a store and parking lot. The latest description data was from 1967 (tho' the datum was NAD83) and this store went up about 10 years ago.

 

When this happens is the benchmark moved or considered destroyed?

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I would be suprised if many people cared about lost benchmarks, aside from hunters from this website or another like it. We don't really need them anymore, as maps are in great abundance & within easy access. We have found a benchmark baried under some grass. We did uh, nothing. We should've reported it on the benchmark page, but you really can't do anything aside from that, right?

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I went looking for my first benchmark today and found that the area is now a store and parking lot. The latest description data was from 1967 (tho' the datum was NAD83) and this store went up about 10 years ago.

 

When this happens is the benchmark moved or considered destroyed?

The best you can do with this mark is to log it as 'Not Found' since you didn't see the disk. It is possible that the disk is under the pavement (or building). We have several in our town that are below the pavement, but there is an access cover to get to them. There is one in our golf course. It is under one of the greens and we didn't think they would like us digging it up to verify it. :lol:

 

Unless you actually saw the disk removed, or know of an eye witness, it is best to log it as Not Found. If you know the contractor who did the construction then you could talk to him and find out how he dealt with the disk.

 

John of 2oldfarts

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I would be suprised if many people cared about lost benchmarks, aside from hunters from this website or another like it. We don't really need them anymore, as maps are in great abundance & within easy access. We have found a benchmark baried under some grass. We did uh, nothing. We should've reported it on the benchmark page, but you really can't do anything aside from that, right?

:D What kind of grass was it under? & NO, you cannot take the disk :D

 

Right you are, you can't really do anything else except make a note of the coordinates & take a picture to post along with on this website.

 

No matter, Just have Fun hunting & sometimes finding that one really excetpional mark...like an old 1871 8ft. rock cairn!

 

109008_400.jpg

 

Shirley~of 2oldfarts

 

:lol:

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I went looking for my first benchmark today and found that the area is now a store and parking lot. The latest description data was from 1967 (tho' the datum was NAD83) and this store went up about 10 years ago.

 

When this happens is the benchmark moved or considered destroyed?

It would be considered a "not found". By all means, tell what you have found in the text.

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We walked up to zero, and there was just normal, green grass there, along the side of the street.

 

If you mean you went to the position indicated by your GPS, you may not have been exactly in the right place.

 

Our consumer GPS receivers, wonderful though they are, are simply not that precise. Also, many 'benchmarks' - the term used on this site to denote any survey point included in the National Geodetic Survey database - are real bench marks, that is, they are placed to indicate elevation, not horizontal position.

 

On the NGS datasheet (found via an unprominent link on every benchmark page), it may say that the horizontal coordinates are 'scaled,' in which case the location is roughly somewhere within 600 feet of the indicated location. That's why experienced benchmarkers use the geographic coordinates and their GPSr to get to the general area, then use the text description to actually find the mark. Remember, most of these descriptions were written before GPS equipment came into common use and were intended to direct a professional surveyor to the point as efficiently as possible. (At least I think that's the purpose; sometimes the prose is a bit mangled and hard to decipher.)

 

-ArtMan-

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What abut this case:

 

Benchmark is in the wall, six feet up, of a building. Building was destroyed many, many years ago, confirmed by twn officials and local residents.

 

In this case, it was clearly destroyed even though you cannot find the actual disk. Should it be logged as such?

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In this case, it was clearly destroyed even though you cannot find the actual disk. Should it be logged as such?

I'd think in that case it should be loggable as destroyed for both CG purposes and NGS purposes.

 

For the NGS, I'd try to get a photo of where the disk would have been and/or any paperwork proving the building being demolished (newspaper article might work) and send it in to Deb at NGS.

 

For CG, log it as destroyed and why you think it's destroyed. Since there's nothing for anyone to find, I can't see it being left as a "found" unless you want to claim it in your count.

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NGS quote: If you did not find the actual marker, then you should enter notes concerning evidence of its possible destruction as text records and select "Not recovered, not found" as the condition of mark

 

See example below..

 

SG0053 ***********************************************************************

SG0053 DESIGNATION - 612

SG0053 PID - SG0053

SG0053 STATE/COUNTY- MI/HOUGHTON

SG0053 USGS QUAD - CHASSELL (1975)

SG0053

SG0053 *CURRENT SURVEY CONTROL

SG0053 ___________________________________________________________________

SG0053* NAD 83(1986)- 47 07 20. (N) 088 34 00. (W) SCALED

SG0053* NAVD 88 - 186.155 (meters) 610.74 (feet) ADJUSTED

SG0053 ___________________________________________________________________

SG0053 GEOID HEIGHT- -33.80 (meters) GEOID99

SG0053 DYNAMIC HT - 186.184 (meters) 610.84 (feet) COMP

SG0053 MODELED GRAV- 980,763.7 (mgal) NAVD 88

SG0053

SG0053 VERT ORDER - FIRST CLASS II

SG0053

SG0053.The horizontal coordinates were scaled from a topographic map and have

SG0053.an estimated accuracy of +/- 6 seconds.

SG0053

SG0053.The orthometric height was determined by differential leveling

SG0053.and adjusted by the National Geodetic Survey in June 1991.

SG0053.WARNING-Repeat measurements at this control monument indicate possible

SG0053.vertical movement.

SG0053

SG0053.The geoid height was determined by GEOID99.

SG0053

SG0053.The dynamic height is computed by dividing the NAVD 88

SG0053.geopotential number by the normal gravity value computed on the

SG0053.Geodetic Reference System of 1980 (GRS 80) ellipsoid at 45

SG0053.degrees latitude (g = 980.6199 gals.).

SG0053

SG0053.The modeled gravity was interpolated from observed gravity values.

SG0053

SG0053; North East Units Estimated Accuracy

SG0053;SPC MI N - 261,140. 7,881,120. MT (+/- 180 meters Scaled)

SG0053

SG0053 SUPERSEDED SURVEY CONTROL

SG0053

SG0053 NGVD 29 - 186.167 (m) 610.78 (f) ADJ UNCH 1 2

SG0053

SG0053.Superseded values are not recommended for survey control.

SG0053.NGS no longer adjusts projects to the NAD 27 or NGVD 29 datums.

SG0053.See file dsdata.txt to determine how the superseded data were derived.

SG0053

SG0053_MARKER: DD = SURVEY DISK

SG0053_SETTING: 36 = BUILDING

SG0053_STAMPING: 612

SG0053_STABILITY: B = PROBABLY HOLD POSITION/ELEVATION WELL

SG0053

SG0053 HISTORY - Date Condition Recov. By

SG0053 HISTORY - UNK MONUMENTED USGS

SG0053 HISTORY - 1948 GOOD NGS

SG0053 HISTORY - 19960717 MARK NOT FOUND NGS

SG0053

SG0053 STATION DESCRIPTION

SG0053

SG0053''DESCRIBED BY NATIONAL GEODETIC SURVEY 1948

SG0053''AT HOUGHTON.

SG0053''AT HOUGHTON, 68 FEET WEST AND ACROSS A NORTH-SOUTH STREET FROM THE

SG0053''NORTHWEST CORNER OF THE DULUTH, SOUTH SHORE AND ATLANTIC RAILWAY

SG0053''STATION, 27 FEET SOUTH OF THE SOUTH RAIL OF THE TRACK, AND SET

SG0053''VERTICALLY IN THE NORTH FACE AT THE NORTHEAST CORNER OF A BRICK

SG0053''BUILDING ACROSS STREET FROM RAILWAY STATION, 1/2 FEET WEST OF THE

SG0053''NORTHEAST CORNER AND ABOUT 3 FEET SIDE WALK.

SG0053

SG0053 STATION RECOVERY (1996)

SG0053

SG0053''RECOVERY NOTE BY NATIONAL GEODETIC SURVEY 1996 (GAS)

SG0053''THE BUILDING HAS BEEN RAZED. ASSUMED DESTROYED.

Edited by elcamino
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In my opinion if you did not find the actual marker (survey disk or whatever) can you really say its destroyed? NO. There is always the chance (however slim it may seem) the person looking for it is in error. There have been a few times when I was so sure a mark was destroyed only to realize later on when I got a WAAS capable GPS receiver that the mark was just described in a vague way and it was not really where I interpreted the description to place it.

 

If you cannot find the disk, its not found no matter how confident you are its really destroyed. Thats the way it has to be or there will be countless marks reported as destroyed that may really not be. Just Because a survey mark is destroyed or not found does not mean it ceases to be of importance.

 

Thats my opinion, I have seen many a survey mark (not just BM's) claimed to be lost, only to be found in good condition right where they were supposed to be.

 

Reminds my of one of our P.S. and his hunt for Plat Corners. The original plat was dated in the late 1800's. Many of the local surveyors had reset the corners over the years from the best evidence they could find and some of it seemed really shaky. We survey a stretch 10 miles long for the acquisition of ROW for widening of the highway to 5 lanes. When the survey was complete it became evident some of the reset plat corners were not in the correct location. So we set out to find the original corners. To make a long story short, we found several of them buried as much as 6 feet deep. Took a backhoe to undercover 2 of them. So for some 50+ years they were thought to be lost and all the time they were just buried.

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In my opinion if you did not find the actual marker (survey disk or whatever) can you really say its destroyed? NO. There is always the chance (however slim it may seem) the person looking for it is in error.

I understand what you are saying and for marks set in the ground I completely agree (although even then I have a few reservations - but let's get through this issue first.)

 

If a disk is set in a structure (in this case the wall of a building) and then entire structure is gone, wouldn't it be resonable to declare the station/mark is destroyed? We do have the issue of making sure the person is looking in the right place, but if it can be shown that the building has been raized that the mark is destroyed?

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In my opinion if you did not find the actual marker (survey disk or whatever) can you really say its destroyed?  NO.  There is always the chance (however slim it may seem) the person looking for it is in error.

I understand what you are saying and for marks set in the ground I completely agree (although even then I have a few reservations - but let's get through this issue first.)

 

If a disk is set in a structure (in this case the wall of a building) and then entire structure is gone, wouldn't it be resonable to declare the station/mark is destroyed? We do have the issue of making sure the person is looking in the right place, but if it can be shown that the building has been raized that the mark is destroyed?

That more in line with my thinking on the issue as well. In this case the building was posiitivley identifed in the description as the police station, and positivley verified as having been destroyed by the town that owned it. I even spoke to a few people who remembered seeing the disk and what wall it was in.

 

I have absolutley no doubt its gone, and the disk, if it still exists, either resides in the dump with the rest of the residue or as a souveneir at someones house, but is definitly no where it is supposed to be.

 

Well, there are some tiny parts of the wall embedded into the back retaining wall that holds the hill above the parking lot that now resides at that location, so I guess in that way I have found the remains of the foundation that supported the structure the disk was mounted in, not unlike finding the concrete pads that a water tower once rested on.........

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But the point is, who has the ultimate say in weather its gone or not. I know you are confident its gone and I don't doubt for one moment it isn't BUT all marks must be considered as 'not found' when you do not find it. Weather its destroyed or not is not your call to make, its NGS and they require proof in the form of the destroyed disk. You all are trying to rewrite the guidelines they have for reporting.

 

If you were there when the building was being torn down and can document it, it may be another story. If they start relaxing the guidelines for reporting destroyed marks how can the have any confidence in the reports if there is no confirming evidence except for someone saying its so?

 

What did R. Reagan says about the Russians bombs, Trust but verify"

 

btw - Destroyed marks are not removed from the database, they are just block from normal searches but if you know the PID you can see the data-sheet.

 

a destroyed mark below, RR came through in 2001 with heavy equipment and mowed down a lot of brush at road intersections destroying or mutliating anything that stuck up about the ground. 2 BM's that I know off are gone.

ECHO-1.jpg

Edited by elcamino
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But the point is, who has the ultimate say in weather its gone or not.

Deb at NGS has the ultimate say. We gather the evidence and send it to her. If she agrees, it's "destroyed". When all is said and done, that's the rule. Period - end of story.

 

btw - Destroyed marks are not removed from the database, they are just block from normal searches but if you know the PID you can see the data-sheet.

True, you can retrieve them if you check off that you want to see destroyed marks. So it's not like it's permanently removed from the database, just removed from normal consideration. Much like the "skull" icons here on GC.

Edited by GeckoGeek
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btw - When you report a mark as destroyed she will put in the report the name of the person who reported it as destroyed.

 

 

*** NOTE - The station below is destroyed.

 

1 National Geodetic Survey, Retrieval Date = JANUARY 3, 2004

SG0213 ***********************************************************************

SG0213 DESIGNATION - CRAB MIGS 1934

SG0213 PID - SG0213

SG0213 STATE/COUNTY- MI/HOUGHTON

SG0213 USGS QUAD - CHASSELL (1975)

SG0213

SG0213 *CURRENT SURVEY CONTROL

SG0213 ___________________________________________________________________

SG0213* NAD 83(1994)- 47 07 22.63266(N) 088 35 28.10958(W) ADJUSTED

SG0213* NAVD 88 - 183. (meters) 600. (feet) SCALED

SG0213 ___________________________________________________________________

SG0213 LAPLACE CORR- -14.88 (seconds) DEFLEC99

SG0213 GEOID HEIGHT- -33.67 (meters) GEOID99

SG0213

SG0213 HORZ ORDER - THIRD

SG0213

SG0213.The horizontal coordinates were established by classical geodetic methods

SG0213.and adjusted by the National Geodetic Survey in February 1997.

SG0213

SG0213.The orthometric height was scaled from a topographic map.

SG0213

SG0213.The Laplace correction was computed from DEFLEC99 derived deflections.

SG0213

SG0213.The geoid height was determined by GEOID99.

SG0213

SG0213; North East Units Scale Converg.

SG0213;SPC MI N - 261,258.415 7,879,268.949 MT 1.00000992 -1 09 00.2

SG0213;UTM 16 - 5,220,055.841 379,311.461 MT 0.99977901 -1 09 58.2

SG0213

SG0213: Primary Azimuth Mark Grid Az

SG0213:SPC MI N - 26 F 158 37 57.7

SG0213:UTM 16 - 26 F 158 38 55.7

SG0213

SG0213|---------------------------------------------------------------------|

SG0213| PID Reference Object Distance Geod. Az |

SG0213| dddmmss.s |

SG0213| SG0212 26 F 454.142 METERS 1572857.5 |

SG0213|---------------------------------------------------------------------|

SG0213

SG0213 SUPERSEDED SURVEY CONTROL

SG0213

SG0213 NAD 83(1986)- 47 07 22.62921(N) 088 35 28.08545(W) AD( ) 3

SG0213 NAD 27 - 47 07 22.88700(N) 088 35 27.65100(W) AD( ) 3

SG0213

SG0213.Superseded values are not recommended for survey control.

SG0213.NGS no longer adjusts projects to the NAD 27 or NGVD 29 datums.

SG0213.See file dsdata.txt to determine how the superseded data were derived.

SG0213

SG0213_U.S. NATIONAL GRID SPATIAL ADDRESS: 16TCT7931120056(NAD 83)

SG0213_MARKER: DD = SURVEY DISK

SG0213_SETTING: 0 = UNSPECIFIED SETTING

SG0213_STABILITY: D = MARK OF QUESTIONABLE OR UNKNOWN STABILITY

SG0213

SG0213 HISTORY - Date Condition Report By

SG0213 HISTORY - 1934 MONUMENTED MIGS

SG0213 HISTORY - 20031119 DESTROYED NGS

SG0213

SG0213 STATION DESCRIPTION

SG0213

SG0213'DESCRIBED BY MICHIGAN GEODETIC SURVEY 1934 (WHB)

SG0213'IN HANCOCK, ON FIRST POINT OF LAND EAST OF OSCEOLA POINT ON

SG0213'HANCOCK SIDE OF PORTAGE LAKE, 15 FEET BACK FROM SHORE LINE

SG0213'TO WEST AND SOUTH. STATION IS U.S.C. AND G.S. AND STATE SURVEY

SG0213'STANDARD DISK IN CONCRETE. NO ELEVATION HAS BEEN DETERMINED

SG0213'FOR THIS STATION.

SG0213

SG0213 STATION RECOVERY (2003)

SG0213

SG0213'RECOVERY NOTE BY NATIONAL GEODETIC SURVEY 2003 (DB)

SG0213'THIS REPORT WAS SUBMITTED BY MICHAEL RAFFAELLI.

 

*** retrieval complete.

Elapsed Time = 00:00:01

Edited by elcamino
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Sorry for following up on this so late.

 

Our first benchmark (JZ0339 in HamiltonCounty/Cincinnati/OH) was also of the "not found" or "lost"? kind of problem. Sorry if my story bores you, but if not, I'd certainly like your comments on it.

 

The description of the benchmark mentions the intersection of two named roads, and we searched and searched all the area. Nothing. The only thing we found was a much newer benchmark right beside the road. So, naturally we assumed the original one was destroyed or removed when the roads were extended, and a new one was placed. But, we could not find the new one in the NGS database... It bears the inscription of the Hamilton County Engineer. (See also the photo at the log http://www.geocaching.com/mark/details.asp?PID=JZ0339)

 

What do you think of the case? Lost or not found? Does anybody know more about this apparently additional local branch of benchmark points that are not included in the official NGS database? Do they also exist in other counties/states?

 

Thanks for your comments,

 

Holger from HoPri

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The mark you were looking for, JZ0339, should be logged as a not found. You saidn in your post that you found the intersection of the roads, but you said nothing of finding (or not finding) the wingwall for the 12 inch culvert that the mark was to be set in. You may want to revisit the site and look again - it may still be there.

 

The mark you found is a Hamilton County Engineer's benchmark, while JZ0339 is described as a City of Cincinatti disk. You could contact the Hamilton County Engineer if you are interested in the purpose and/or data for that partcular mark. I did see that they have a website simply called The Hamilton County Engineer's Website in Cincinatti, Ohio. (I also noticed that the Engineer's office has a display of historic surveying equipment.) All counties in the nation have a County Surveyor or Engineer that sets and maintains survey control for their county. Most larger cities do also, a good example being shown by the designation of the mark in question.

 

You'll find many types of survey control (brass disks, pipes, nails, lath, flagging, etc.) in your benchmark hunts, but not all of it, (most of it, most likely) is not in the NGS database. The NGS marks we search for are geodetic control on a national level. Similar survey control can be found at state, regional, county, and city levels, as well marks set by private sector surveyors and engineers. Most of these marks are not in the NGS database.

 

Good luck on your hunts.

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First of all, thanks for your reply post.

 

>The mark you were looking for, JZ0339, should be logged as a not found.

 

I came to the same conclusion, but only eventually (I had to edit my log several times...). At first, I was completely convinced that the old one must be gone. But now I agree that one cannot be sure of a destruction unless it is approved by an official or witness.

 

> You saidn in your post that you found the intersection of the roads, but you said nothing of finding (or not finding) the wingwall for the 12 inch culvert that the mark was to be set in. You may want to revisit the site and look again - it may still be there.

 

The culvert was the main feature we looked for, and that we were not able to find, and true, the log is not specific in this respect. I assume that it takes a lot more experience with the interpretation of features mentioned in benchmark descriptions to have a very clear picture of what you really look for. I only recently learned that poles like the one that marks NO8370 are called witness posts... :-O

 

> I did see that they have a website simply called The Hamilton County Engineer's Website in Cincinatti, Ohio. (I also noticed that the Engineer's office has a display of historic surveying equipment.)

 

I also ran across this page when I tried to find information on the new disk. But I found no way to check for a specific 'PID'. But it is an interesting page.

 

> All counties in the nation have a County Surveyor or Engineer that sets and maintains survey control for their county. Most larger cities do also, a good example being shown by the designation of the mark in question.

 

This is very interesting. Do you happen to know what decides whether they are registered in the central NGS database (like most of the Cincinnati BMks seem to be)? Or does the NGS database contain only BMks placed long ago?

 

> Good luck on your hunts. B)B):blink:

 

Thanks again, and same to you!

 

Ho from HoPri

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