Benchmark Ll1321

[+Team Laxson]

Here's a link the Benchmark listing:

http://www.geocaching.com/mark/details.aspx?PID=ll1321

 

Here's where I'm confused: From the 1974 NGS note:

"THE AZIMUTH MARK WAS NOT FOUND AND IS BELIEVED TO HAVE BEEN DESTROYED. A NEW AZIMUTH MARK WAS SET AT THIS TIME."

 

If the mark established in 1974 is found, should it count as a recovery on the PID (LL1321) established in 1935, or should there be a new PID for the new azimuth disk set?

[Bill93]

To claim a find on LL1321 you are looking for the main disk which the description says

STATION MARK DISK IS STAMPED 5262

The description is a little confusing, so it may also be stamped JUNCTION. It will NOT say AZ or AZIMUTH or RM on it.

 

The azimuth mark is usually about 1/4 mile away for the old triangulation stations and typically further for ones set since the 1970's. The azimuth disk helps the user of the main station to quickly establish his directions in order to locate and measure other points. Unusual here, the data sheet does not give even an approximate distance to the az mark. You need to study the description and area landmarks to estimate it.

 

Some but not many azimuth marks have their own PID and geodetic data sheet, but here I don't see that for either the old one or the 1974 one. They only have a file number with no data.

 

The 5262 is the approximate elevation, which was sometimes used as the named designation of the mark. The current elevation value (using the current datum for reference) is a few feet different at 5269, which shows that it is a bad idea to stamp the elevation. However, someone intended the designation to be JUNCTION and that is what it says is stamped on the reference marks.

 

Note that the latest NGS Data Sheet LL1321 shows that the power squadron did not find LL1321 in 2001, so you may have a bit of a challenge. That report is not, however, convincing evidence that it is gone so you may wish to prove them wrong.

 

This station has ADJUSTED horizontal coordinates, so your handheld unit should take you within a few feet. If you can find the reference marks or the flagpole you could tape to find a more precise location and determine if there is any sign of the disk.

Edited March 7, 2006 by Bill93

[+Black Dog Trackers]

Team Laxson -

 

I agree with all that Bill93 said. I want to add a couple more points.

 

Some stations in the NGS database have one or more marks associated with them. One could say that there is a main station mark and some associated marks. These associated marks can be Azimuth marks, Reference marks, and occasionally Witness marks. Associated marks have an arrow across the center of the disk, and around the outer edge of the disk, they say which kind of associated mark it is.

 

In order to be able to log a Find for a PID, you must find the main station. However, even if you don't find the main station and therefore have to log a Not Found for it, it is perfectly appropriate for you to upload pictures (both closeup and distant) of any associated marks you find, and their Lat-Lon coordinates you find for them with your GPSr.

 

If you look at the datasheet that Bill93 indicated, you will find what is called the "box score", an ascii box that gives each associated mark with its distance and bearing from the main statin. The box score is often useful for finding associated marks from the main station, or vice versa. In the case of LL1321, there are 5 associated marks for the main station, which is called JUNCTION. (Oddly, RM 4 is also an Azimuth mark.)

 

In some cases, an associated mark has its OWN PID. In those cases, you can log a find on these associated stations because they have their own PID. Nearby station WANAKA AZ MK is an example. It is an associated mark to WANAKA and both WANAKA and its associated station WANAKA Azimuth mark have their own PIDs so you can log them indepenedently. WANAKA also has 2 other associated marks, RM 1 and RM 2 but those don't have their own PID, so they would have to be part of a log of WANAKA or perhaps WANAKA AZ.

Edited March 7, 2006 by Black Dog Trackers

[68-eldo]

Team Laxson -

 

In some cases, an associated mark has its OWN PID. In those cases, you can log a find on these associated stations because they have their own PID. Nearby station WANAKA AZ MK is an example. It is an associated mark to WANAKA and both WANAKA and its associated station WANAKA Azimuth mark have their own PIDs so you can log them indepenedently. WANAKA also has 2 other associated marks, RM 1 and RM 2 but those don't have their own PID, so they would have to be part of a log of WANAKA or perhaps WANAKA AZ.

 

What is the thinking behind giving an RM its own PID? Is this only because of the way it was moumented or is there another purpose?

 

For example TU0629 has two RM within 100 feet and they both have their own PIDs TU0628 and TU0630

[Papa-Bear-NYC]

 

What is the thinking behind giving an RM its own PID? Is this only because of the way it was moumented or is there another purpose?

 

For example TU0629 has two RM within 100 feet and they both have their own PIDs TU0628 and TU0630

 

I have found in many cases that RMs to triangulation points are later used as Bench Marks (Vertical Control Points). In other words, some agency runs a level line through an area and since there's a nice disk sitting there, they use it.

 

Good example is "Palisades" (KU3890).

 

Now here's a Triangulation Station from 1898 that didn't even have any Reference Marks set till 1930. Palisades was one of the principal triangulation points is the work done in Greater New York in the early part of the twentieth century.

 

Then in 1956, the C&GS comes along and makes Palisades RM1 and Palisades RM2 Bench Marks. (See KU1644). Notice that this has altitude adjusted and location scaled. The main station mark (see above) is the reverse.

 

So this type of thing is just using a solid mark for a second purpose. An irony of this one is that from the main station datasheet for Palisades, it gives the location of RM1 to the centemeter (although it's not "adjusted" in the technical sense), but the dumb-dumbs that filled out the datasheet for Palisades RM1 (the Bench Mark, i.e. KU1644) scaled the location and put it on the wrong side of the George Washington Bridge!

 

Another example is "SPY" (KU0913) and "SPY RM1" (KU0912). SPY was surveyed as a triangulation point (with it's RM) in 1930, and then both the Station Mark and the Reference Mark were surveyed as Bench Marks in 1952. Once again SPY RM1's location is scaled, but at least the description is a verbatum copy from the datasheet for SPY - and they also got the scaled coordinates much closer, but still not nearly as good as is given on SPY's datasheet..

 

So check the datasheets carefully and you can usually figure out why an RM gets a separate PID. Often times it's for a second use as a Bench Mark.

Edited March 10, 2006 by Papa-Bear-NYC

[2oldfarts (the rockhounders)]

68-eldo asked

What is the thinking behind giving an RM its own PID? Is this only because of the way it was monumented or is there another purpose?

 

An RM having it's own PID means that it was set with standards that met the NGS criteria and was submitted as such.

 

Kewaneh or one of the other surveyors, that let us pick their brains for neat little details, may have something else to divulge about this.

 

It is cool that when you recover some triangulation stations...you get to log '3' for one stop.

 

Have fun hunting!

 

Shirley & John