NGS data sheets

AZ mk CJ8178. The NGS search for that pid returns ‘not found’ 

So if it is just an azimuth mark it does not have a position. The "box score" shown only lists an azimuth to it, no distance, so no position was computed. 

I found some info for CJ8178...

DD="No descriptive Text Available"

NN="No Geodetic Control"

There are a lot of marks (reference marks, azimuth marks, TBM, etc) that have PID's but are not published

@larry-scott I'm not sure if it is of any significance but I found quite a few PIDs that start with CJ and they all come up with the DD indicators for H and V. and they all tended to be az or ref marks for the main point and the main point always had a different  beginning designator like DP. I did find one mark in Minnesota that shows as destroyed with a CJ PID and horizontal and vertical information. It almost appears as if they have changed the publication of the datasheets. Does that happen that an NGS point has a published datasheet then years later that information becomes non-published? Attached are some data sheets sh

owing what I found.

I have seen az mk with approx coords and elevation. But it is near a 2nd order bench line. And posted position in 5 decimal position and mm elevation. 

But its pid data sheet should be somewhere. The older search engine had an option for data sheets of older marks known to be destroyed. 

frustrating. My fault having lost the data sheet. But there’s a cluster of 3 marks. MON 97, and 2 RMs. The az mk appears to have been leveled to and positioned. So, why it’s not in the engine is sad. 

thanx

The main station is JV3369

Not sure why it wouldn't come up for your search.

From inventory by Mason and Dixon Line Preservation

@gary_g mon 97 is nearby. In the box score CJ8178 for some reason the data sheet is gone. I occupied it only 3 yrs ago.

I occupied CJ8178 because it was published position and elevation. And I was observing to the north. So it didn’t matter which mk I occupied since (what I believe is th az mk) it was equally as good for the purpose. 

It’s not a deal breaker, but it’d be good to have proper documentation. 

I found a data sheet! It is published by county survey department. And many of the county control have NGS data sheets. But that doesn’t explain why its PID is not in NGS data base. So, that ends that dilemma  

I was on the NGS datasheet committee for the last 15 years of my service.  The vast majority of reference and azimuth marks for triangulation stations never had a well determined horizontal position which is the case with this specific mark.  Once a mark has a well determined position and published as part of the National Spatial Reference System those data are always available except under some very extreme conditions which is not the case here.  The position from Washington County is one they had determined and was never submitted for publication to NGS.  I should point out that whoever designed their datasheet needs some training in basic geodetic positioning - there are no guidelines or specifications for determining 3rd-order GPS-derived orthometric (NAVD 88) heights.

As always there are exceptions. This is one in the vast minority. Around here many counties used NGS and USGS control monuments for county control networks. Trust but verify. Normally they are trustworthy. The note for the Washington County sheet that says GPS established in 2003 but tied to NSRS 2007 would be a red flag for me around here.

 NK0705 ***********************************************************************
 NK0705  DESIGNATION -  HUBBARD EAST BASE AZ MK
 NK0705  PID         -  NK0705
 NK0705  STATE/COUNTY-  IA/STORY
 NK0705  COUNTRY     -  US
 NK0705  USGS QUAD   -  ZEARING (2018)
 NK0705
 NK0705                         *CURRENT SURVEY CONTROL
 NK0705  ______________________________________________________________________
 NK0705* NAD 83(1996) POSITION- 42 10 49.20185(N) 093 15 03.31991(W)   NO CHECK
 NK0705* NAVD 88 ORTHO HEIGHT -   312.1   (meters)     1024.    (feet) VERTCON3
 NK0705  ______________________________________________________________________

Posted by: @base9geodesy

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I should point out that whoever designed their datasheet needs some training in basic geodetic positioning - there are no guidelines or specifications for determining 3rd-order GPS-derived orthometric (NAVD 88) heights.

Also no statement regarding which projection is being used. That's kind of a glaring omission. 

Posted by: @base9geodesy

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I was on the NGS datasheet committee for the last 15 years of my service.  The vast majority of reference and azimuth marks for triangulation stations never had a well determined horizontal position which is the case with this specific mark.  Once a mark has a well determined position and published as part of the National Spatial Reference System those data are always available except under some very extreme conditions which is not the case here.  The position from Washington County is one they had determined and was never submitted for publication to NGS.  I should point out that whoever designed their datasheet needs some training in basic geodetic positioning - there are no guidelines or specifications for determining 3rd-order GPS-derived orthometric (NAVD 88) heights.

Would they delete old datasheets though? I can't imagine they would even if the information was bad. Maybe post it with a correction so that people that used it before can decide whether they will make adjustments.

"Would they delete old datasheets though?" -- It has to be something exceptionally drastic for NGS to actually delete a station from the Integrated Data Base (IDB).  There are however several thousand bench marks along the Gulf Coast (TX to FL) for which their NAVD 88 heights use to be published but have  now been suspended due to considerable subsidence in the region but the datasheets are still available.  Those values can usually be retrieved by requesting the datasheets by their PID and checking the box "Include suspect heights in vertical motion areas"

It struck me odd that this AZ mark, std NGS disc, has an NGS PID. But no longer in the DB. 

I realize it doesn’t have a true position or elevation by NGS. And AZ marks in general have minor use. The AZ isn’t updated with current adjustment. 

And the county knew of the disc. Incorporated it the county net. I had occupied it a few years ago. Well I now wanted to flesh out a doc and didn’t remember that I had used the county publishing. A PID should be a forever. Even marks known destroyed the data sheet is still available. 

I was frustrated. But having found the country sheet I realize that’s what I used. So just a dive into why a PID is not in the DB. 

All the ancillary marks triangulation marks (RMs & AZ MKs) have PIDs they just don't normally have either an accurate horizontal position or height so they don't have their own datasheets.

There are, I think, 9 existing passive brass marks set by the NGS or it predecessors within or very near the limits of my fair city. They are all beautiful in my eyes. Of these only one has GPS derived coordinates on it. That one was set and measured some 25 years ago. Since then trees have grown up around it rendering it un-GPS'able. The others were all set in the days before GPS and, save 1, are now un-GPS'able (5 due to vegetation, 2 due to buildings)  and probably always were.

I've established what I consider to be good geodetic coordinates on all of them by setting 3 nearby references in GPS'able locations, resecting a position for my TS, and tying the NGS mons with the TS. 

It is disappointing that OPUS Shared makes no provision for ties of this sort.    

Here’s a beautiful thing. MIDDLE 1st order H&V, 1935. I of course took 90 min with Z-12, opus returned 1cm. 

Then tragedy. It was plowed out just recently.