I'm Finding Discs Ngs Has Listed As Destroyed

[+Klemmer]

Last weekend, while walking a road looking for other benchmarks, I kept finding discs that were not in the NGS database. OK, not uncommon at all. Of course, not in the GC.com database either.

BUT - after a little data digging, I found that two of these discs HAD BEEN in the NGS database, but were listed as destroyed!!! Yet - there are the discs, right in the pictures, and firmly installed in their concrete pads, not loose or anything. The "to reach" descriptions and disc markings are correct. What the heck?! Any theories on what is going on here? Should I ask Deb to "un-destroy" them, if she can? Any other reason they may have been destroyed? Retro-active bad data discovered?

 

Details (pics on my own website; click for higher resolution if you have wide-band connection or are patient)

DX3251 (X 423) 1935

DX2924 (62 P) 1933

 

To see the NGS Datasheets you will have go to the NGS PID search page; you can use This NGS Link, then type in one or both PID number(s), click on "Include Destroyed Marks", and click on 'Submit".

[for some reason, you can't link directly to a destroyed datasheet].

 

Notice that DX3251 has been recovered once after it was destroyed, and DX2924 has been recovered twice after it was destroyed. [sort of a time machine thing going on here... ] Can you really do this? Or is it some database weirdness?

 

While we are on the subject of finding destroyed discs, here is another one, sort of. Except I can't pin down the PID number. It is just a half mile or so up the road from DX3251, at about N33°56.446', W117°52.948.

?423 Disc Name

It looks like someone intentionally wanted the first letter to be unreadable. There are (or mostly were) a whole series of these discs (a level line, I think is the term) along Brea Canyon Rd. Literally A423 thru Z423. They are so close, and the "to reach" descriptions so similar, I haven't been able to figure out which one this is, but I have very little doubt it is also "destroyed". Problem found with it? Hmmm?

 

Any experts out there like to shed any light on my confusion?

Edited April 19, 2006 by Klemmer & TeddyBearMama

[Papa-Bear-NYC]

Last weekend, while walking a road looking for other benchmarks, I kept finding discs that were not in the NGS database. OK, not uncommon at all. Of course, not in the GC.com database either.

BUT - after a little data digging, I found that two of these discs HAD BEEN in the NGS database, but were listed as destroyed!!! Yet - there are the discs, right in the pictures, and firmly installed in their concrete pads, not loose or anything. The "to reach" descriptions and disc markings are correct. What the heck?! Any theories on what is going on here? Should I ask Deb to "un-destroy" them, if she can? Any other reason they may have been destroyed? Retro-active bad data discovered?

...

I've found two in Manhattan that were on the destroyed list.

 

I asked Deb (together with various supporting pictures etc. that in fact the right marks are still there in the right places) and she said log a recovery as good, and she would mark them not destroyed or (un-mark them, what ever). She's been off line for a while so the status is still destroyed, but eventually I expect they will find their way back into the database.

 

I guess the key here is why they were declared destroyed. One was declared destroyed in 1974. There is a log of "Good" followed by a log of "Destroyed". It's on a stone wall. Maybe the wall was moved. But there was no explanation in there as why it was declared destroyed. Maybe the NGS keeps some back up information. Then there was a "Good" logged in 1995 by the New Jersey Geodetic Survey (professionals, no?) and my log in 2005. Check it out: KV0584.

 

Here it is:

 

This is why I don't like the rule of thumb, that you should not first put a detailed "Not Found, presumed destroyed" entry in there before having it officially declared destroyed. Or else put the same detail in the "Destroyed" entry. That way in the future, should the mark mysteriously reappear, folks will know to disregard it . Another reason not to set a destroyed mark that you have possesion of in your front yard.

Edited April 19, 2006 by Papa-Bear-NYC

[+rogbarn]

You can get a head start on looking for destroyed markers by going to yearly archives section of the NGS site, choosing your state and click on Get Misc Files. One of the options is nonpub - Station list of all non-published stations in the state. It's a simple one line per station but it does give you PID, designation, coordinates and a couple of other items. Once you identify possible entries, go to the PID menu and select them by PID as you did before.

[+Klemmer]

Thanks, Roger, nice tip!

I wasn't specifically looking for destroyed stations, they just happen to jump out at me. The other ways available to get them are not nearly as neat.