What does this mean?

[+genegene]

In benchmark MZ0452 it says Note: disc set away from marker etc... Does this mean one was placed or should be placed? and if placed, how far away do they place them?

[ArtMan]

In benchmark MZ0452 it says Note: disc set away from marker etc... Does this mean one was placed or should be placed? and if placed, how far away do they place them?

The original datasheet reads in part:

 

MZ0452_U.S. NATIONAL GRID SPATIAL ADDRESS: 18TXM552938(NAD 83)

MZ0452_MARKER: Q = CHISELED SQUARE

MZ0452_SETTING: 36 = SET IN A MASSIVE STRUCTURE

MZ0452_SP_SET: PIER BASE

MZ0452_STABILITY: B = PROBABLY HOLD POSITION/ELEVATION WELL

MZ0452

MZ0452 HISTORY - Date Condition Report By

MZ0452 HISTORY - UNK MONUMENTED B+ARR

MZ0452 HISTORY - 1934 GOOD NGS

MZ0452

MZ0452 STATION DESCRIPTION

MZ0452

MZ0452'DESCRIBED BY NATIONAL GEODETIC SURVEY 1934

MZ0452'0.2 MI N FROM WASHINGTON.

MZ0452'ABOUT 0.2 MILES NORTH ALONG THE B. AND A R.R. FROM THE STATION AT

MZ0452'WASHINGTON, 50 FEET NORTH OF THE NORTH RAIL ON THE TOP OF THE WEST

MZ0452'CORNER OF THE SOUTHEAST PIER BASE OF A RAILROAD WATER TANK, AND LEVEL

MZ0452'WITH THE GROUND. A CHISELED SQUARE. NOTE--SET CONCRETE BOUND WITH

MZ0452'STANDARD DISK AWAY FROM WATER TOWERS, AS WATER DRIPPING FROM TANK IS

MZ0452'DETERIORATING CONCRETE.

 

It could be more artfully written, but to me the NOTE at the end seems to be advisory, urging that a standard disk be set in concrete away from the water tower, not that an actual disk has been so set.

 

I could be wrong.

 

-ArtMan-

[+d-town cachers]

if i had to guess, i would say that after verifying the bench, the surveyor set a tbm or other form of tie, as a refernece to that bench, (which seems to be set in concrete that is getting dripped on which is eroding it away). could be wrong, but if i was looking and read that description, i'd be looking for a tie close by.

[+genegene]

TIE ? TBM ? what do thoes mean im a nubie? and how far away 1,2,3ft or like 10 to 15 ft? the location is off in the weeds and young trees are scatered arround and i will be neading a rake just to get a better look at the ground becouse of all the leaves and decaing matter, not that im complaning, just wondering. and also what are the markers made of? I have acces to a metal detector..

Edited April 11, 2007 by genegene

[+Kewaneh & Shark]

... to me the NOTE at the end seems to be advisory, urging that a standard disk be set in concrete away from the water tower, not that an actual disk has been so set...

 

Generally, in surveying notes that state "SET.... ", it is a description of what was set, not an advisory note of what should be done.

 

Most likely, the survey crew was there to use MZ0452, in this case a chiseled square on a concrete base. They saw that the concrete - essentially the benchmark - was being eroded by the water dripping from the tank. They probably set a standard disk in a concrete mound (not 'bound' as described) away from the tower and the water. It is curious that there is no further description of the mark they set.

 

An example of an advisory note can be seen on MZ0453 which states "...A CHISELED HIGH POINT. THIS BENCH-MARK SHOULD BE CHANGED TO A BRASS DISK SET IN ABUTMENT..."

 

Both MZ0452 & MZ0453 were recovered by the NGS on January 1, 1934. It would stand to reason that the same crew recovered both marks. Why they would reset one mark for permanence and then only advise in the notes that another should be reset for a similar reason is puzzling. It could be that MZ0452 was weathering faster than MZ0453.

 

TIE ? TBM ? what do thoes mean im a nubie?...

 

A 'tie' is a reference mark. Multiple reference marks can be used to relocate or reestablish a point, corner, or other survey mark. Other names are 'swing ties' or 'spreaders'. (While the practical use of reference marks, ties, & spreaders is virtually identical, their construction and distances from the marks differ. Reference marks are usually constructed like benchmarks and are placed about 100 feet from the referenced mark. Ties can be chiseled crosses on concrete, spikes or nails and shiners set in power poles or fence posts, or a multitude of other things, and are usually set within 100 feet of the referenced mark. Spreaders are usually nails set within a few feet [1'-5'] of the referenced mark.)

 

TBM is an acronym for Temporary BenchMark.

 

- Kewaneh

[ArtMan]

Generally, in surveying notes that state "SET.... ", it is a description of what was set, not an advisory note of what should be done.

 

... It is curious that there is no further description of the mark they set. ...

 

- Kewaneh

Exactly. Odd as it might be to suggest that a new mark be set because the old mark is being eroded; it's even odder, it seems to me, to say you DID set a mark, but then not say WHERE it is. What's the point?

 

Of course, the information could have been in the hard copy record that never got entered in the NGS datasheet.

 

Bit of a mystery here.

 

-ArtMan-

[+jwahl]

As an aside: I think that often the original station descriptions were written by one C&GS crew to others involved in the initial observations. In some cases monuments might be set first, then "observed".

 

For a tri station there might be crews to build a tower, to observe, for light keepers return to get to the point, occupied on several occasions and sometimes even later better monument the point, etc. The famous "To get to" instructions were written primarily for those initial groups to get to the point. Not much thought was made about future recovery. Thus you see "follow the tire tracks up the hill" type of things in instructions on occasion. The terse nature of some of those descriptions and transcriptions over the years can make them confusing to a modern interpretation.

 

In this case it does sound to me like an observer giving advice to others to reset the station at some point in the future. It would appear that nothing was done unless there is another station in the database nearby. Of course a reset station would require additional observations to tie it into the system and that work would then be external to the original levelling and be a pain to deal with and maintain.

 

So if you look at it in the context of an instruction rather than a final description SET can take different meanings.

 

jwahl

 

Generally, in surveying notes that state "SET.... ", it is a description of what was set, not an advisory note of what should be done.

 

... It is curious that there is no further description of the mark they set. ...

 

- Kewaneh

Exactly. Odd as it might be to suggest that a new mark be set because the old mark is being eroded; it's even odder, it seems to me, to say you DID set a mark, but then not say WHERE it is. What's the point?

 

Of course, the information could have been in the hard copy record that never got entered in the NGS datasheet.

 

Bit of a mystery here.

 

-ArtMan-

[+genegene]

ArtMan where would i find a hard copy of the original record, if one exists?

[+Kewaneh & Shark]

Generally, in surveying notes that state "SET.... ", it is a description of what was set, not an advisory note of what should be done.

 

... It is curious that there is no further description of the mark they set. ...

 

- Kewaneh

Exactly. Odd as it might be to suggest that a new mark be set because the old mark is being eroded; it's even odder, it seems to me, to say you DID set a mark, but then not say WHERE it is. What's the point?

 

Of course, the information could have been in the hard copy record that never got entered in the NGS datasheet.

 

Bit of a mystery here.

 

-ArtMan-

 

And that is the point I was making. I do think that there was another mark set at the location of MZ0452. I would also agree that there were measurements taken to the new mark but that the data either did not get forwarded to the NGS, or not entered into the NGS bluebooks. My logic lies in the meaning of the word 'set' as used by surveyors, and the clearly stated advisory note found in he description for MZ0453.

 

- Kewaneh

[ArtMan]

ArtMan where would i find a hard copy of the original record, if one exists?

Good question. I don't know if the original sheets were retained after the datasheets were typed (by female federal prisoners, as I believe has been mentioned in these forums previously), or even IF they were retained. Perhaps they are in NGS headquarters in Silver Spring, Maryland. Or a government warehouse somewhere.

 

I don't know if they are accessible for special inquiries, but I don't recall hearing about any plans to make them widely available (e.g., scanned and posted online). It would be an expensive undertaking. Unfortunately, when the original conversion to machine-readable format was made (in the 1908s?), there was no cost-effective way to scan and store non-text.

 

I've occasionally run across datasheets that refer to "accompanying drawing" or "map," so I imagine that in many (some? most?) cases, there was a diagram originally included in the file. Having seen local datasheets that incorporate maps of the immediate area, and even photographs, I know first hand that in finding a benchmark, a picture can indeed be worth 1,000 words. If graphical finding aids for hard-to-recover marks still exist, it would be a shame if they are not accessible.

 

-ArtMan-

[68-eldo]

Unfortunately the major impetus to convert the files is that they take up too much room. Can you imagine how many file cabinets are needed to hold all the data sheets?

 

The earliest technology to reduce this kind of paperwork was microfilm. While that medium was good it was rendered nearly useless in some cases by giving the work to the lowest employee on the totem pole. That employee was then rated by quantity not quality. So a simple thing like checking the focus of the camera was neglected. Then the bureaucrat asks why do we need the paper when we have it on microfilm? So the paper was thrown away and the file room was converted into the office of the Vice President for Contemplating Navels.

 

I have found most microfilm to be nearly useless. An example: A number of years ago my aunt showed me a genealogy chart created by a Mr. Von Beck Canfield in 1912. The chart took that branch of our family tree back to 1200s in some cases. She allowed me to take it to work to copy off on the copy machine. It did not work that well and not all parts of the chart are readable as my aunt’s copy was barely readable. The original chart was kept in the New York Public Library. So I sent a request to them and they sent me a microfilm reproduction of the chart. It is not as readable as the copies I made. Unless I can follow in Von Beck’s footsteps and see the original documents he saw (not the microfilms) that part of my family tree maybe lost.

 

Sorry for the rant.