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Benchmark ?'s


goldfishy
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<_< I'm interested in finding/logging benchmarks. I think I have been bypassing a lot along the way! I don't quite understand how they work, though. Can we log a benchmark if someone else has already found one? Or do they work just like caches, where everyone can log them? Second, how do we know if we officially found the correct item, if the item is unidentified? For example, I went out for a certain benchmark, which I am familiar with. Another person already loggged it 'missing'. I think I found one, if not two, of the benchmarks related to this. Who confirms whether we are right? And, finally, what the heck are triangular str (...??) benchmarks? Any help would be greatly appreciated! :mad:
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Goldfishy,

 

This has really been discussed at great length here on the forum, so rather than have another go at it, I would like to invite you to try looking at both the FAQ page Here: http://www.geocaching.com/mark/

 

And please read this entire thread which is a pinned topic started by the 2oldfarts: http://forums.Groundspeak.com/GC/index.php?showtopic=79709 Unfortunately there is no quick and dirty answer, but between those two you should come away with a well rounded set of answers for your questions and we all would be more than happy to help any other questions you have going forth from there...

 

Thanks for your interest, I am sure we will have you off and hunting like a pro in no time!

 

Rob

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For goldfishy and other newcomers, I will clue you in on a couple of hints that took me a long time to figure out. There are often several disks associated with one "station" (that's the official word for benchmark). Some stations, known as triangulation stations for the old-fashioned way they were originally set and measured, often have two reference marks nearby. Those are disks, usually within a 100 foot radius, usually with arrows on them pointing to the main station. If the station is called BEDFORD, they will normally be stamped BEDFORD RM1 and RM2. About a half-mile away due north or south will be a so-called azimuth mark, in this case stamped BEDFORD AZ MK. Many newbies will find a reference or azimuth mark and claim a find for the main mark. This is not correct. Sometimes those reference or azimuth marks will have their own PIDs (like AA1111), but not always. If you're lucky, you might log four disks in one compact area.

 

The other thing is reset marks. Sometimes when a station is destroyed, a new mark will be set in the same area to replace it. If the old mark was FROST, the new one might be FROST RESET or FROST 2, and, perhaps with rare exceptions, the existence of the new mark indicates the original one is gone. It's easy to log the original mark when you've actually found the replacement, since they are typically very near each other. A good double-check is the "STAMPING" line on the official NGS datasheet, accessible via the "view original datasheet" link.

 

-ArtMan-

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Here is a simple description of a Bench Mark, found it USE manual.

 

Bench mark    A mark on a fixed and enduring object indicating a particular elevation. It is used as a reference in topographic surveys, tidal observations, and construction.
Edited by elcamino
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Artman wrote:

 

<<The other thing is reset marks. Sometimes when a station is destroyed, a new mark will be set in the same area to replace it. If the old mark was FROST, the new one might be FROST RESET or FROST 2, and, perhaps with rare exceptions, the existence of the new mark indicates the original one is gone. It's easy to log the original mark when you've actually found the replacement, since they are typically very near each other. A good double-check is the "STAMPING" line on the official NGS datasheet, accessible via the "view original datasheet" link.>>

 

Figures I would find the exception to the "stamping" rule :P

 

Check out OTIS LK0571 and OTIS 2 LK0789.

 

I visited this area 4 times over 6 weeks because of the "stamping" line in the NGS Data Sheet for OTIS 2:

 

LK0789_SETTING: 7 = SET IN TOP OF CONCRETE MONUMENT

LK0789_STAMPING: OTIS 2 1991

LK0789_MARK LOGO: CGS

 

I looked, and looked, and looked for a disk stamped OTIS 2, even though the description fit that of OTIS in every way. Even being in a cemetery, I wondered if it might be an underground mark :P

 

And I didn't go to the OTIS Data Sheet since I had found that mark and didn't think there was anything more to it.

 

The problem was (and I only figured it out this evening :( ) that OTIS had been determined to be destroyed by the NGS because of possible movement, and I needed to visit the Data Sheet for OTIS where it said:

 

LK0571 HISTORY - Date Condition Report By

LK0571 HISTORY - 1935 MONUMENTED CGS

LK0571 HISTORY - 1939 SEE DESCRIPTION CODH

LK0571 HISTORY - 1991 DESTROYED NGS

 

LK0571 STATION RECOVERY (1991)

LK0571

LK0571'RECOVERY NOTE BY NATIONAL GEODETIC SURVEY 1991

LK0571'STATION HAS POSSIBLY MOVED. GPS OBS TO THIS POINT DID NOT

LK0571'FIT THE POSITION FOR THIS POINT. OTIS 2 (NOT STAMPED AS SUCH)

LK0571'WAS CREATED WITH THE GPS OBS. SEE OTIS 2.

 

Mystery solved! OTIS 2 1991 is stamped OTIS 1935!!

 

But now a new question arises. If this monument/disk was thought to have moved, why would it be used again?

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There are often several disks associated with one "station". Some stations, known as triangulation stations often have two reference marks nearby. Those are disks, usually within a 100 foot radius, usually with arrows on them pointing to the main station. About a half-mile away due north or south will be a so-called azimuth mark. [Snipped for brevity.]

 

ArtMan:

 

Great information! I've almost completed my recovery of EZ-0914, which contains all of these elements. I believe the Azmith mark has a missing disk (I found a stem in a concerte base), but I was interrupted by business duties before I could finish my confirmation measurements.

 

Just to prove that survey crews, like the rest of us, occasionally have a bad day, ponder this memo about the arrow on one of the reference marks:

 

RM 3 (ARROW DOES NOT POINT TOWARD BRIGGS 2) IS A STANDARD DISK STAMPED BRIGGS NO 3 1933, SET IN THE TOP OF A SQUARE CONCRETE MONUMENT THAT PROJECTS 2 INCHES.

 

I can picture the scene as the crew is packing up their gear for the day.

 

"What's that, Chief? The station's over THERE? And the #@*% cement has dried? Oh well, we'll fix it in the description.....Let's go get some beer!"

 

-Paul-

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The station's over THERE? And the #@*% cement has dried?

Usually, the concrete monuments were precast, not cast in place. That meant that if the arrow did not point toward the station, there was more to it than just turning the cap in the wet cement. It meant turning the whole monument - all several hundred pounds of it. Also, it's my understanding that the monuments were not always set by the survey crew that took the measurements and made the original report. This meant that if the survey crew who found it pointing the wrong way and had to describe it, might not have had the tools or resources to turn to the proper direction.

 

- Kewaneh

Edited by Kewaneh & Shark
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fwiw

 

The old 8 inch square concrete posts the predate the late 40's were precast and weighed around 200 lbs and took a couple of men to set them. The 12-in sq and round ones were poured in place.

 

The instrument team did not set the marks, the building team did. Instrumentmen were better utiliized doing what they did best, the survey observations.

 

fyi (circa 1935)

 

BM_post_tool.jpg

Edited by elcamino
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The station's over THERE? And the #@*% cement has dried?

Usually, the concrete monuments were precast, not cast in place. That meant that if the arrow did not point toward the station, there was more to it than just turning the cap in the wet cement. It meant turning the whole monument - all several hundred pounds of it. Also, it's my understanding that the monuments were not always set by the survey crew that took the measurements and made the original report. This meant that if the survey crew who found it pointing the wrong way and had to describe it, might not have had the tools or resources to turn to the proper direction.

 

- Kewaneh

This one must have been set by the same crew, except the reference mark was set in an outcrop. No moving it after the fact!

 

The crew who recovered it in 1993 must have been, um, praising , the work of the original crew, especially when they were hunting a station buried 2 feet deep. In 1993, they noted

 

REFERENCE MARK NUMBER 3 IS STAMPED RM 2. IN THE ORIGINAL DESCRIPTION, IT WAS STATED THAT THE REFERENCE MARKS WERE SUPPOSED TO BE SET WITH THE CAST LINE OF EACH DISK POINTING IN THE DIRECTION OF THE STATION, INSTEAD IT WAS DISCOVERED THAT THE INSCRIPTION ON THE DISK READS IN THE DIRECTION OF THE STATION.

 

Here is RM 2 (or is it 3?) with the arrow pointing to the station.

 

LY2619_RM_2_orientation.jpg

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Usually, the concrete monuments were precast, not cast in place. That meant that if the arrow did not point toward the station, there was more to it than just turning the cap in the wet cement.

 

Paul responds:

 

Thanks for the clarification. Since many disks are embedded in cement railway signal foundations, cement stairways, etc., I assumed that the disks were added to monuments on-site.

 

This is a good example of why we keep you Old Pro's around.....to tell us how it REALLY was! ;)

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In the situations where the monuments are found set in foundations, the sides of buildings, stairways and such, they were certainly added after the fact. Usually with a manual rock drill and cement.

 

Sometimes, the survey crew did set the monuments, but, as ElCamino stated, it was usually a different crew altogether. Think of it in terms of your DOT - the survey crew is not the same group that lays the asphalt, or repairs the guardrails, or maintains the landscaping. Each person has a part.

 

I've found marks that were constructed both ways - precast and cast in place. LQ0161 in Tooele County, Utah had good evidence that it was cast in place as the form boards were still intact around the monument.

5712_100.jpg

 

There is a cast in place monument near 36° 19.72'N, 120° 43.61'W. It is not in the NGS database. It is a standard USGS brasscap dated 1939 on an 8" square pedistal, similar to ElCamino's description. My dad's 90 year-young aunt lives about a mile down the road from it. She told me that when she was young her dad - my great-grandad - was contracted to cast the concrete monuments for a large survey project that the government was conducting. (She said she remembers building forts out of the monuments in the yard.) While my great-grandad was not a surveyor, he was one of the building team.

 

This is a pic of me with my great-grandad's monument...

384c2bd3-9ca5-4e96-88cb-b97b4624373a.jpg

 

- Kewaneh

Edited by Kewaneh & Shark
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Me & Bucky (or would that be You & Bucky)

 

Regarding OTIS and OTIS 2, look at the email correspondance below I had with the NGS about these two points back in 2001:

 

 

Hi Mark! This point was recently (within the last year) observed again with GPS and again, as in 1991, it was determined that OTIS (LK0571) had somehow moved and the original position was no longer correct. OTIS 2 (LK0789) is the point redetermined by the GPS observations and this position should be used in all field work. We could not determine if the original post had been uprooted, or if the original observations were bad.

Burton Smith

NGS, N/NGS43 Records Management Branch

(301) 713-3184

 

--------------------------------------------------------------------------------

 

Subject: Discrepancy with C&GS station

Date: Mon, 21 May 2001 11:21:15 -0600

From: "Mark Johannes" <mark@clarklandsurveying.com>

Organization: Clark Land Surveying

To: "Deb Brown" <Deb.Brown@noaa.gov>

 

Coordinates from your data sheet for Station "OTIS" (PID LK0571) and for "OTIS 2 (PID LK0789) show the two monuments approx. 7.5 feet apart. The monument in the field stamped "OTIS 1935" appears to be in the location of "OTIS 2" as described in the data sheet. Using the reference marks for "OTIS", it appears to me that this is the case. Is it possible that when the crew went out to set "OTIS 2" prior to GPS observations that they found "OTIS" still in concrete which was torn out during expansion of the cemetery? Could they have simply reset "OTIS". Please do not hesitate to contact me if you need additional information, or if you are able to determine what happened. Thank you, Mark Johannes, PLS

Clark Land Surveying, Inc.

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<_< Hmmmmm...I'm still confused with the finding of benchmarks. I think I have it...maybe now. For example, I think I found MF1312. It is identified as a church spire. Does this mean the spire, or is there still a disc to find? I found what looks like it may be a disc, but it was really hard to get close to take the picture. (I was already getting a lot of funny looks snooping around the church as it was.) I went to log what I thought was finally a benchmark find, and noticed the other cachers did not include a picture. So that made me wonder, what proof is there when finding a benchmark? (If there is no log, no pictures, etc.) And are benchmarks not included in one's total finds? Thanky much for any help! <_<
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Gold fishy,

 

Here is how to approach these.

 

This is a landmark station, the surveyors usually do not place a brass disc on them, but if they do so, the information will be made note of in the narrative on the Datasheet. Usually these are an intersected point, meaning they trained the survey instrument, usually known as a theodolite back in the day, at a place on a landmark and measured the angles the instrument was pointed in both the horizontal and vertical plane, then they did the trigonometry involved in locating the location of that point based on the information from the places they were when they looked at it from the ground.

 

Once the location is triangulated they could go to a new place on the ground which has not been yet established to help establish it. A sort of leap frogging around by triangulation, if you will, based on the fact that all survey in that day was optically, line of site based. Mathematically you need to know two places to determine the location of a third.

 

Landmarks used as intersected points were up high, and allowed the geodetic surveyor tie in in places that would have otherwise require very tall towers erected to see from place to place. If you could see a tall place from many places on the ground nearby, you could speed the process of locating the where of all the places you are surveying are. Keeping in mind that they are trying to establish the latitude and longitude of these locations. These stations were usually considered third order survey accuracy, some were at one time considered of second order value but the decision was made at some point to downgrade landmarks to third order. It was an ease of use situation, it located things on the ground to third order accuracy, so as to establish a survey network and precisely locate areas, and do so more cheaply than the longer and more involved surveys with more triangulation's per higher order, and tall towers to accommodate the need for higher accuracy.

 

So let's look at your church steeple;

 

'DESCRIBED BY COAST AND GEODETIC SURVEY 1944 (FN)

They originally did this in 1944, the person who wrote the description, the chief of the survey party's initials are FN

 

MF1312'STATION IS LOCATED IN THE NE ANGLE OF THE INTERSECTION OF

MF1312'SOUTH ELLSWORTH STREET AND EAST BENTON AVENUE IN THE CITY

MF1312'OF NAPERVILLE.

Go to this city and stand in this intersection. Look northeast. this should be a church named NAPERVILLE SS PETER PAUL CH, if not, you may not have the original church. Is it still belonging to the same congregation? is it still a church?

 

THE CHURCH AND SPIRE ARE OF RED BRICK CONSTRUCTION.

Are they? Confirm this. If not, this may not be your church. Go inside and see if the Church leaders know about the buildings history.

 

MF1312'THE SPIRE HAS A GRAY SLATE ROOF WITH OPEN BELFRY AND A CLOCK FACE

MF1312'ON FOUR SIDES.

The roof may have been replaced since then but are the four clocks still there? If not, Go in and ask what is going on.

 

THE OVERALL HEIGHT IS 215 FEET

A story of a building is oh about 10-12 feet high so does this look to be about 20 stories high?

 

AND THE

MF1312'CONSTRUCTION WAS COMPLETED IN 1925.

Can the owners of the church confirm the buildings age for you or has the visual already confirmed this without asking?

 

MF1312'

MF1312'THE BASE OF A CROSS LOCATED AT THE PEAK OF THE SPIRE WAS

MF1312'THE POINT SIGHTED.

This is the spot that the surveyors trained their instrument on when they used this spire for triangulating other places, and this place as well. There was no mention in the description of a disc mounted on the spire, and the Datasheet states: MF1312_MARKER: 90 = CHURCH SPIRE so there isn't a station disc. Does this spire still have a cross? Some do not, if not, this may not be the original spire. Remember, the original one did.

 

You can also use this information: NAD 83(1997)- 41 46 30.59710(N) 088 08 41.63694(W) ADJUSTED Take that latitude and longitude that the surveyors in 1944 determined, load that in your GPS using the settings for degrees minutes and seconds mode, NAD 83 Datum, ( and yes the correct datum does very much matter ) Make that a waypoint then run a "go to" to that waypoint on the GPS to confirm that the GPS points at the spire. The accuracy on your GPS is not as accurate as third order triangulation is so your GPS should point right at it for the most part. The GPS is good for 5-10 feet accuracy and third order Triangulation is good to less than six inches accuracy. If it does not point at the station, er ah, spire, as you circle the building, pointing at the spire exactly, this may not be the original spire or spire location. I have found remodeled churches with relocated spires, an that is a not found. It has to be the original item in the correct location. In many many cases, there is no need to big deal this as you will see at a glance whether you have or do not have what you are looking for, even if you are in the right place. That's right! It isn't you, it is the landmark! :-)

 

The big point is that on the geodetic survey marker, the find is not as much the object itself as it is the accuracy attached to the object in ensemble. You will read about this in the attached letter from Burt Smith of NGS just above this post in his correspondence with Mark Johannes, a surveyor and geocacher. The station accuracy is important. If the station is disrupted and moves, all the calculations are off. On Landmarks, this is not something the NGS can control so they generally just consider the station lost or destroyed but on their own monumentations, they can generally re-survey and correct the data if need be, happy that the station is still in the ground.

 

Ok, Enough on the NGS aspect. Here is the geocaching lowdown. There is no rule that requires you show proof for the benchmark find, whereas a cache log signing is really necessary in geocaches or the cache owner can remove your credit for the find. However most people feel that if they have a digital cam, Why not prove it, so this Photo for proof has become accepted practice. The Geocaching scoring schema seems to only give credit for the benchmark find. It is a shame that they give no credit for the Not Found as they are equally hard to, ahem, not find, Mostly. :-) Most folks seem to go with the all statistics route. They keep track of it all and there are many ways of going about it.

 

The three benchmark hunters I have learned the most from, in how they go about this keeping of unofficial score, and it seems like a good fair, and accurate scheme to use for this are 2oldfarts, Black Dog Trackers, and Seventhings. All three of these people, and it is a Husband and Wife team on the 2oldfarts part, have all written some great posts about how they work the bench mark scoring they follow, so I will leave it to them to direct you to the posts they have made in the past so you can brush up on that if you like. The benchmark finds are a separate total from the cache finds. Several of us who are regulars here in the Benchmark Hunting are proud owners of the 0 caches found total. Seventhings is the over 1000 benchmarks 0 caches found leader. There are many who are doing well in both arenas as well.

 

Good Luck and Happy Hunting Holidays!

 

Rob

Edited by evenfall
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I have found remodeled churches with relocated spires, an that is a not found.  It has to be the original item in the correct location.  In many many cases, there is no need to big deal this as you will see at a glance whether you have or do not have what you are looking for, even if you are in the right place.  That's right!  It isn't you, it is the landmark!  :-)

 

A couple of weeks ago I went hunting for GLENWOOD CHURCH CUPOLA. When I got there, I thought the church looked a little too modern, and the description of a hexagonal half dome didn't match what I saw in front of me. Then I noticed an old bronze bell sitting as a kind of memorial in the back lawn. It was warped and broken, as if from a fire.

 

As I was looking at the bell, an official came out of the neighboring house and politely offered assistance (as in "What is this strange guy in an orange vest doing wandering around our church property?"). I explained, and asked if the church had a fire. He became eager to help and explained that the original church had burned to the ground in a fire on Christmas Day, 1982. The church now on the property was an entirely new structure. He also took me inside to show me photos of the old church and photocopies of the news articles. The original church was a beautiful building and it must have devastated the small community when it was lost. I managed to get a somewhat clear photo of the photo and posted it with my log.

 

All in all, one of the more interesting discoveries I've had while benchmark hunting, even though it was a no find and I logged it in Geocaching as destroyed.

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