A Reference Mark with its own Reference Marks?

[+Klemmer]

Here is an interesting situation: There once existed Triangulation Stations DX4828 (UNION) and DX4796 (118), and they each had several Reference Marks (RM's), and 118 even had an Azimuth Mark. They are both destroyed, and no NGS datasheets seem to be retreivable, as far as I can tell. But I would like to see them, if someone knows how to pry them out of the NGS system, if they still exist.

 

Then it gets a little strange. Even though there was never a "UNION 118" (as far as NGS the database knows), there now exists a UNION 118 RM 3 (DX4815), which is active, and I have recovered. It seems to have it's own RM's, namely UNION 118 RM 4 and UNION 118 RM 5.

 

So, now there is an RM (with a PID), with it's own RM's. By the way, a new Tri station was established nearby (DX4817, UNION 118 2), of which UNION 118 RM 3 is an RM. I think we are three levels deep in RM's !!

 

We have

1) UNION 118 2 Tri Station, H adjusted

2) UNION 118 RM 3, which is an RM of UNION 118 2, and is also H adjusted.

3) UNION 118 RM 4 and UNION 118 RM 5, which are RM's of UNION 118 RM 3

 

I have recovered 1) and 2). I'll go back to look for 3). Probably in nasty brush, in a nature preserve.

 

Anyone else ever find RM's with RM's?

[Bill93]

To find destroyed mark data sheets, go to the NGS search by PID and check the "include destroyed marks" box. Unfortunately it oesn't also work for "No geodetic control marks".

 

If you read the codes that come up for your stations and compare them to a couple other "destroyed" stations, one vertical and one horizontal control, you see the coding is different.

 

- H Nonpub HORIZONTAL CONTROL NONPUB REASON

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

- X Surface Mark Reported Destroyed

- N No geodetic control at this mark

-

- v Nonpub VERTICAL CONTROL NONPUB REASON

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

- X Surface Mark Reported Destroyed

- D No Descriptive Text available

- N No geodetic control at this mark

 

>DX4828 UNION..............................33 53 47.1/117 53 49.1..........3 D

>DX4828 UNION..............................33 53 47.1/117 53 49.1..........3 NN

>DX4796 118...................................33 53 47.2/117 53 49.1..........1 D

>DX4796 118...................................33 53 47.2/117 53 49.1..........1 NN

>MH0137 A 112................................41 01 55. /092 48 09.....................X

>MG0866 CEDAR RAPIDS GRACE EPIS CH 41 58 54.2/091 39 54.5..3 X

 

So DX4828 and DX4796 are not "destroyed" but rather the NGS decided whatever data they had on them was not satisfactory for geodetic control and made them unpublished. I haven't digested the available information on your marks to intelligently guess why. A possibility is that they put in the newer mark DX4815 to have a first order mark in the neighborhood, and even though the old mark was up to some lower order standards with respect to more distant marks, it violated the accuracy requirement versus the new and nearby first order mark. In that case, they would probably archive the data and make it unpublished.

[mloser]

Here is my take on it:

 

UNION was set at some unknown date in the past and the datasheet has since disappeared. The sheet you printed for it indicates that no descriptive text is available. Nearby BREA UNDERGROUND seems to have been set in 1938 but the first datasheet entry is for 1974.

 

In 1969 a survey party (CA-059) wanted to use UNION couldn't find it. They grabbed RM3 and surveyed to it instead, then submitted it as a second order horizontal mark, putting it in the database.

 

In 1974 the NGS came around and put in UNION 118 2, a combo of UNION and 118, both of which had gone MIA for some reason, surveyed it to first order, and remeasured to the old RMs and set some new RMs. The new station is pretty far from RM3 at 100 meters--I wonder how close it was to old 118?. RM 3 kept its PID and second order status. All the talk about an underground mark under RM3 may be fluff, as the NGS said in 1974 it couldn't find any evidence of it.

 

HERSHEY RM 3 near me is a reference mark surveyed to third order because the main station was not very usable, but in this case they explained the process a bit.

 

Bill93's post (which got to the board while I was creating this one) brings up a good thought--UNION and 118 may both still be there, but since you don't have the descriptions they may be a bit hard to find!

Edited May 8, 2007 by mloser

[+Black Dog Trackers]

Anyone else ever find RM's with RM's?

 

I grepped the .txt files that I got from BuckBrooke a few months ago and found these:

 

CY0442 LUZENA RMA RM4

CY0623 LUZENA RMA RM5

DA1187 STOVAL RM5 RMA (based from DA1087 which has quite a bizarre history with 2 AZ marks and a dug up and re-set RM)

HT2257 TURK RM1 RM3

JV6553 HEREFORD RM2 RM3

JV6554 HEREFORD RM2 RM5

DD2625 LITTLE RIVER RM5 RMA

CK3157 BETHEL RMA RM3

CK4372 BETHEL RMA RM4

DD2732 VAUGHT RMA RM3

DD2734 VAUGHT RM6 RMA AZ MK

 

I read the datasheets on the first few, but not all.

 

Of course these are (or seem to be) RMs of RMs that have their own PID. (Some may have RMs of their own, I didn't look at them all.) There are probably lots of other RMs of RMs that don't have their own PID.

 

I didn't look for RMs of AZs or vice versa.

[+seventhings]

Here's an AZ with two RMs. The AZ has a PID but the two RMs are no-PIDs.

 

LOW AZ - KK0074

 

Interestingly, LOW AZ is the AZ for station LOW (PID = KK0060), but station BROW (PID = KK1588) serves as the AZ for LOW AZ.

 

Will

Edited May 18, 2007 by seventhings

[+Klemmer]

So that makes BROW an AZ of an AZ. Cool!

[+seventhings]

Definitely. A LOW-BROW, A-to-Z connection.

 

Another AZ nearby, HILL AZ, also has its own RMs

 

HILL AZ KK0493

 

Will