An Interesting Find

[+Spoo]

Today, I went looking for Benchmark OC0585, Designation D28, in Maine. I did not have high hopes for it knowing that this area has been heavy in logging and gravelling for many years.

The written description and co-ordinates led me right to the spot.......

 

BUT I found a USGS benchmark labeled:

 

TT/BT 2

1940

Elevation 515

 

Mounted in an 8" square of concrete and elevated from the ground about 3 inches.

 

This especially intrigues me since I have found NGS Benchmarks labeled with such markings as:

 

TT 17 BT (OC0547)

 

Are such things coincedence? Can anyone enlighten me? Do these letters/numbers actually mean something?

[+GEO*Trailblazer 1]

Most of the TT's and TTC's ## here are Elevation bench marks on the Topographic map.

I found this by asking,and recieving for the Control Data from the Quadrangle Surveys.

I think that they were not the accuracy needed to enter in the NGS data base.

 

If you would like to get the information I speek of in the Top Right hand corner of the Topographic Maps is a # for the Quadrangle,write the Department of the Interior and ask for the control for that map.

[+rogbarn]

It is my impression that it is not unusual to have a NGS and a USGS marker near each other. They are used for different purposes and if the first one is not in a good position for the second agency to take advantage of, or perhaps can't even be found, then they will just place their own mark.

 

Also, I understand that the way USGS marks get into the NGS database is when someone uses the USGS mark for their own purposes and then submits the data to the NGS. So, it is not the USGS accuracy that is a problem (although that might also be an issue), it is just that not very many of them get used and measured for projects that are submitted to the NGS.

[+Colorado Papa]

Talk about unsual locations! How about this one?

 

HK0501'RECOVERY NOTE BY NATIONAL GEODETIC SURVEY 1977

HK0501'STATION MARK WAS THE ONLY MARK RECOVERED. IT IS IN GOOD CONDITION

HK0501'AND IS IN ITS ORIGINAL POSITION BUT IT IS IN THE BASEMENT OF A LARGE

HK0501'HOUSE THAT WAS BUILT OVER THE MARK. MR. WILLIAM THACH, OWNER OF

HK0501'THE HOUSE SAID A LETTER WAS SENT TO OUR OFFICE IN 1963 OR 1964

HK0501'REQUESTING THAT THE STATION BE MOVED BEFORE CONSTRUCTION OF

HK0501'THE HOUSE BEGAN BUT DID NOT RECEIVE AN ANSWER AND NO ONE CAME

HK0501'TO MOVE THE STATION. HE HAS PRESERVED THE STATION MARK ALL

HK0501'THESE YEARS BECAUSE HE KNEW HOW IMPORTANT IT WAS.

 

This is not a find, yet. Think I'll try next week when I head that direction if the home owner is agreeable.

[Z15]

Info from DaveD (NGS)

 

The U.S. Geological Survey (USGS) - www.usgs.gov, is a Federal agency in the U.S. Department of Interior. Among their varied roles is the responsibility for the national mapping program. Since 1879 they have been tasked with the development of the U.S. national mapping program. The National Geodetic Survey (NGS) is in the Department of Commerce, and was founded in 1807 as the Survey of the Coast. The name was changed in 1836 to Coast Survey, 1878 to U.S. Coast and Geodetic Survey and finally in 1970 to NGS. NGS has the responsibility for the development, implementation and maintenance of the national horizontal and vertical geodetic datums. USGS has established tens of thousands of survey monuments tied to the national reference system defined by NGS. The USGS monuments were established almost exclusively to support the national mapping program and are in most cases of lowered accuracy than the work performed by NGS. Unfortunately, due in large part of significant budget cuts in the 1980's, very little of the USGS control work was ever submitted to NGS for inclusion in the National Spatial Reference System. With the growing capabilities of GPS, USGS sets very few monuments any more. One of their most interesting monumented surveys is the annual monumentation of the South Pole

[DaveD]

Spoo -- note that OC0547 is not an NGS disk, but rather a USGS mark from 1940. NGS and our predecessor - US Coast & Geodetic Survey (USC&GS) never used the TT (Transit Traverse) designation for survey marks. The number 17 is just a sequential number for this station in the traverse line and BT are the initials of the USGS's chief of party.

[+Black Dog Trackers]

Dave D -

 

Help! Check out HV4400 l just logged over on Theodore Roosevelt Island today. Is the disk supposed to be stamped SCOW USE? If so, I must've found some other disk.

[DaveD]

Black Dog Tackers -- The mark if it's stamped at all, should be SCOW 1932 - the USE in the name indicates that it is a Corps of Engineers disk, which is as stated in the body of the descrirption. There is an error in the NGS data sheet which indicates the mark was monumented by CGS. I will have to send a correction to our data base group tomorrow.

[+Spoo]

DaveD:

 

In my posted log for OC0547, I did note that this was a USGS disc accepted by the NGS.

 

(I also noted and photographed the damaged disc and uprooted monument and filed this info with NGS)

 

I was trying to find out why there where so many USGS benchmarks in my area with TT # BT and what that meant. THANK YOU for the explanation. It was just what I was looking for.

[+Colorado Papa]

This is not a find, yet.  Think I'll try next week when I head that direction if the home owner is agreeable.

HK0501 Benchmark Log. Was disappointed that I could not see HK0501.

[+gbod]

This is not a find, yet.  Think I'll try next week when I head that direction if the home owner is agreeable.

HK0501 Benchmark Log. Was disappointed that I could not see HK0501.

Since there is a house on top of the mark, how usable is this mark in the real world? I'm assuming you can't put any surveying equipment over the mark, so isn't this mark pretty much useless? (until the house is removed?)

[+Colorado Papa]

Since there is a house on top of the mark, how usable is this mark in the real world? I'm assuming you can't put any surveying equipment over the mark, so isn't this mark pretty much useless? (until the house is removed?)

True, but how would you report this to NGS, as destroyed? I don't think so since they had the opportunity years ago. I would have loved to have DaveD's letter of authorization to approach the homeowner and say I was here to remove the benchmark and declare it as official destroyed. In the meantime, guess we have to wait for the house to burn down or get hit by a tornado ( got a better chance of winning the lottery!).

 

BTW, it is a beautiful rambler at a terrific location overlooking the whole area! Was built for probably $20K but now worth $1M after seeing the prices of other homes down below! I'll see if I can post a picture.