New Policy at NGS

I've turned in several mark recoveries since March and none of them have shown up on the database.

They are all passive marks and some are not GPSable.

I don't know what's going on.

Dave,

I DON'T think that this means that the Passive Network (specifically the old Triangulation Stations) are going to disappear from the database, just that Horizontal Positions on the Passive Network will ONLY be "updated" via GPS Observations/Solutions.

I know (or at least suspect) the the NGS is VERY BUSY right now getting NAD83(CORS96a) ready for primetime (should be VERY soon now). Several "housekeeping" chores have been set aside this year (or at least put on the back burner) while the Multiyear Solution was (and is) getting completed and implimented.

Loyal

OK.

Probably nobody else cares but me.

One beautiful 1972 Caltrans brass disk at Mt. Zion in a 12" concrete cylinder is obstructed by trees, a water tank and our lookout tower so I couldn't get a good GPS solution. We dug that monument out because it was down half a foot or so. I had to put a rebar and cap GPS control point 50' away in order to get a good solution.

Another one just like it nearby we had more trouble finding and it was deeper under dirt mixed with chunks of granite. It is under tree canopy but has a nice view of another peak (of course).

Both have RMs that I haven't spent more than a few minutes looking for so I haven't found them.

I also found a benchmark in Honeydew (not hard to find though it's in a box). Someone might care someday but Honeydew is beyond the middle of nowhere in northwestern Humboldt County. It's nice to know if it's still there before driving 4 hours to get there.

I've been visiting quite a few NGS benchmark and tri-station lately. Never have a camera to get a shot. But beautiful views from the top of those mountains!

Dave,

That DOES bring up an interesting point! I'm not aware of any [current] “procedure” for establishing an “eccentric” Station relative to an old USC&GS/USGS/NGS/whatever Passive Network Station (for say an OPUS_db submission), that would get an “updated” Horizontal Coordinate into the National Database (NGSIDB).

These “legacy” Stations are (in many cases) VERY valuable to the local Surveyor, and getting a “modern” geodetic coordinate on them (by using an eccentric station and say a Total Station) is a very good idea.

That might be something that “we” should take up with the NGS.

Say what you will about about the CORS Network (which I REALLY love), the “traditional” Passive Network (going back 200+ years) is a National Treasure (Mike Potterfield's words).

Loyal

We turned in a couple of recoveries on top of Mount Saint Helena one of which is the original 19th century copper bolt. There are several up there (depends on what you want to see).

I agree with Mike Potterfield; I hate to see the passive network just rot away. Everyone wants to save a historic architectural masterpiece building but the public is largely unaware of these marks and their historic significance.

FWIW,

The announcement includes the following: "SUPPLEMENTARY INFORMATION: The National Geodetic Survey has not received a traditional (triangulation or traverse) survey for purely horizontal work since 2006."

My interpretation of this policy is that it merely codifies the reality that conventional terrestrial observations are no longer cost-effective to perform and for NGS to support through the development/maintenance of software tools needed to get the data into the NGS database.

Those points in the NGS database that had not been observed in a GPS project submitted to NGS were NOT included in the new adjustment. Nor shall they be in future adjustments (as far as I know).

As for the matter of updating coordinates for either benchmarks or low-accuracy triangulation/traverse stations, they can be updated via the Mark Recovery Tool. I imagine that many of these points could be updated using OPUS-DB. Those not suitable for GPS are probably of limited utility for conventional terrestrial observations.

I too miss the days when observations were made from remote high points. Packing equipment up to these points was often challenging with the reward of great views.

In the most issue of The American Surveyor there is an article about a student-led survey to determine the heights of the highest points in Texas. Their logistical challenges were certainly less daunting than those in earlier times.

Cheers,

DMM

Mike,

I agree with everything you said above, but bear in mind, that from a “Land Surveyor's” perspective, the REAL VALUE of a modern geodetic coordinate on a “legacy” Passive Network Station, MIGHT be what it WAS USED FOR (and tied to historically), NOT [necessarily] what it might (or might not be) be used for in the future.

Just my 2 bits...

Loyal

Parks had a Surveyor in the 1960s (Dean Jennings) who surveyed a bunch of State Beaches and tied them to the local 3rd order triangulation stations and he would show it on the Record of Survey. That made it really easy to recover the monuments he set and found.

The guy who keeps track of recovery report statistics on the amateur benchmark hunters forum posted this morning that in the last month NGS added 605 GEOCAC recoveries to the data base, bringing them up to about June 24 submission dates.

I'd expect all of your reports before that date are posted to the data sheets.

I was under the impression that they long ago stopped accepting conventional type work. I guess it is now "official".

Before the advent of CORS and HARN, we used conventional stations (triangulation and traverse) to control GPS surveys. Here in the east these stations are often not GPS'able. So, we would set an eccentric and do a conventional tie. One way was to set a pair with GPS and traverse (single shot) to the obstructed station. Another way was to do single GPS station with an astronomic observation. All of the ones I did were for first order (10 ppm) stations. I doubt they would accept that for a 1 ppm survey.

Another issue came up last week. I submitted a vertical project (leveling) for a coule of marks at a navigation lock and dam on the Ohio River. Every lock in the Pittsburgh District (US Army Corps of Engineers) has dozens of survey points, mostly alignment pins but also 4 to 12 "M" marks, which are either disks on gate monoliths or survey pedestals. So, each project (23 locks and dams, 16 reservoir dams) has an a mark called M1, M2, etc up to M4 and beyond. Each lock also has an upstream gage disk and a downstream gage disk.

Anyway, I submitted this small project at the Hannibal Locks and Dam with two new (long existing, but new for the NSRS) marks, HANNIBAL M1 and HANNIBAL US GAGE DISK.

These were renamed M1 and HANNIBAL GAGE DISK in the database. When I asked about it I got the answer that NGS policy is to designate the disks EXACTLY as stamped. Actually, they made a mistake because the gage disk is stamped US GAGE. Since we are going to bluebook marks at each lock, there are going to be multiple M1 marks in the database. I have submitted very few leveling projects, but many (more than 50) GPS projects. This never happened on the GPS side, but they have different "gatekeepers" for GPS and leveling projects. My intent is add additonal stampings to these marks next time I go there, and submit a revised recovery. Not sure how that will go over. But, I do know that there are a multitude of marks in the database that are designated differently than they are stamped. Makes one wonder what is the purpose of having two fields in the database: DESIGNATION and STAMPING.

I also found a benchmark in Honeydew (not hard to find though it's in a box). Someone might care someday but Honeydew is beyond the middle of nowhere in northwestern Humboldt County. It's nice to know if it's still there before driving 4 hours to get there.

Dang Dave you get around!
I lived a few miles from Honeydew for a couple of years. It's a bit out of the way, but I'd say Forks of the Salmon and Happy Camp are a bit past beyond the middle of nowhere. If you get back there see if the Honeydew Store (if it's still there) sells a confection called the Honeydew Hummer....

DJJ

> I don't know what's going on.

My understanding is that all Mark Recovery submissions are sent to the state geodetic advisor for review before publishing. Marti Ikehara, the CA advisor, has been busy doing CBL measurements around the state lately, so she may not have had time to review the submissions yet.

Howdy,

I do not know whether California's NGS Advisor, Ms. Ikehara, does this review. I am pretty sure NGS policy is to encourage submittal of mark recoveries via the Mark Recovery Page.

I do not know why this page is not explicitly linked from the NGS home page.

Cheers,

DMM

> I do not know whether California's NGS Advisor, Ms. Ikehara, does this review.

I've had Marti follow up directly with me on a number of occasions regarding recovery notes I've submitted via the web form. I assumed it's standard practice in all states, but that may not be the case.

NGS has posted another huge batch of recovery reports to the data sheets. They might be up to date on submissions.