m&h

Will-- A neat find, whatever it is. We would think about trying to reach somebody at the National Park Service, or in the park itself. For a few minutes we indulged in a fantasy that you knew about Stephy Tang without having to consult Google. Cheers, m&h

Thanks again, as always, and congratulations to the notables. Cheers,

jemcjb U.S. Dept. of the Interior, National Park Service. Many parks have several or many such marks located here and there within their boundaries, but we've never tried to find a way of locating them or counting the marks in a single park. NPS may have lists; we've just never pursued it. Cheers,

We've never found any tree RMS or tie-ins that we could really count on, so we're responding only to your last question, about re-blazing. Our gut feeling is that re-blazing should be done only by professionals. You might take a page from PFF's book and mark the tree with tape (though that too has its risks, folks with chainsaws having their ways of reading taped trees). But actual alteration of the bark seems to us like bringing stamping equipment along to freshen up a disk. Not for us. By the way, we've greatly enjoyed your shots of older marks in the Oregon mountains. Cheers,

George-- Thanks for the additional detail on the four types of "cup" disks. Incidentally, it's interesting that the disks were called "old-type" in the original setting description, which could have been as little as 2 years after the introduction of the flat-tops, as we have learned from your excellent article. Cheers,

George, We're having a little trouble including our photos in this message, so in case it fails this time, we refer you to our Benchmarking log for SY2731. We finally got a shot of an old "cup" style disk, though its situation is somewhat depressing. The data sheet gives no description of the mark except to say it is lost, but the 1913 edition of CGS Special Publication 13, The California-Washington Arc of Primary Triangulation, gives a thorough description on p. 54. In the second edition, 1922, p. 33, the station is said to be lost. The 1913 description says in part that the station is five yards east of the east line of N Washington Street near the middle of 25th Street, in a boulder 18 by 24 by 30 inches, buried with its top about 5 inches below the surface of the ground. The station is now in the corner of a yard at the northeast corner of N Washington and 25th Streets. The boulder is almost all the way out of the ground and is part of a landscaping feature. The disk is significantly tilted toward the south. Reference marks are located in the data sheet and described in Special Publication 13, but we did not search for them, since the primary point cannot be located with certainty, and the RMs have to be under either pavement or well-kept lawn. The area shot looks northwesterly across the corner, toward N Washington on the N side of 25th. . Would have been nice to find it in place. Cheers,

As ever, many thanks! Cheers,

PS sorry about the meaningless emoticon, which jumped in where we wanted ( to appear. Cheers,

The windmill appears not to be destroyed as far as a surveyor observing it is concerned. However, this is an intersection station, and such marks are almost never used by professionals any more. As you seem already to know, NGS prefers that these not be logged with them unless a definite destruction report can be made. On Geocaching, though, we think you can log it as found, posting the photos to show (a) the dilapidated vanes and ( the relative soundness of the tower.

It's entirely possible that you found one of the thousands of marks that aren't in the database. Who set the mark? (What is the factory-impressed inscription around the outer edge of the disk?) Where was it? Do you have a photo or the coordinates? Answers to these questions will enable more of us here to be helpful. Cheers,

George-- RM4 2590805.84 RM3 0245646.44 Our hasty pocket compass readings were RM 4 246, RM 3 10. Rough, but within a couple of degrees. We’re very grateful for the chance to play with the information you provided. Cheers,

George-- Bravo! Magnificent. Many thanks to you and your database person. Cheers,

Will-- P.S. Wde have not learned how to link. Just tried it, and failed. Sorry.

Will-- That’s a rich find! It may be that reference marks sometimes take their stamped years from the main mark, regardless of whether they may have been set later. We recently found RM 3 for DV2061, PHOENIX BASELINE EAST, set with two reference marks in 1947. The 1962 recovery note contains the sentence “Reference Mark 3 was established at this time.” The mark is stamped “BASELINE EAST NO 3 1947.” See DV2061

Paul-- We started mark hunting in Maine and Nantucket, but we've lived in Washington state for the past several years. We've enjoyed your sagas.

"By the way, is this phenomenon, the reporting of "cloaked" reference marks, characteristic of Mass., or do others of you get to experience the joy of hunting these down? [see, for example, MY2758.]" Paul, we posted an inquiry about this problem a day or two ago, and have not had a reply yet. The case of MY2758 is not as blank as some. The recovery paragraphs give that vague description of the RMs being about fifty feet from the mark and about 120 degrees apart. The "box score" higher up in the datasheet gives the directions to the three marks. It's imprecise, but better than nothing. The "box score" usually also gives the metric distances, but not here. Challenging, eh? Cheers,

As to whether to say "datasheet" or "data sheet," notice that the NGS retrieval page and most of not all of its sub-pages use the one-word form. When you complete a retrieval, it is headed thus: The NGS Data Sheet See file dsdata.txt for more information about the datasheet. So we remain uncommitted. Cheers,

We may be missing something in our reading of the datasheet for ES0782, RANDELL 2, near Joseph City, AZ. This mark was set when RANDELL was threatened with destruction (which did eventually come) by I-40 construction. The mark is a Horizonal Control Mark, and has two reference marks, RM 3 and RM 4 (more on that in a moment). We can't find in the datasheet any precise information about the locations of the reference marks. Now, it's a bare hill and they're both within about 25 feet of the main station and its eight- or ten-foot witness post, so finding them is not the problem. Our question is, are the azimuths and distances from the mark to the RMs on file somewhere? They must be, right? Otherwise the RMs don't refer to much. We suppose that the RMs are numbered 3 and 4 because the original mark used 1 and 2 for its RMs, which ended up with their own PIDs which at this moment are still active in the NGS database (ES0063 and ES0065). We looked diligently, did not find any trace of RM2, but found RM1 in its post yanked out of the ground. We took some pictures, posted logs, and wrote Deb, leaving to her the question whether RM2 is also destroyed. By the way, the two marks nicely illustrate how a mark you can see is obviously destroyed, and one you can't is only possibly destroyed. We will be grateful for learned comment on the datasheet question.

Leveling runs establish precise elevations, but the process very rarely includes precise horizontal location. The surveyors used maps to locate the marks after they were set. All that's necessary for an elevation mark is a pretty good idea about how to find it. When it is used as the basis for elevations on a project, the project itself will be horizontally located by other means, when necessary. All this, though, suggests that it really can be helpful for us to submit handheld coordinates for scaled marks. As to the usefulness of marks in poor condition: a horizontal control mark may have some usefulness left in it if the center of the stem can be located. But if you come on a broken stem of an elevation mark, there is no way to usefully estimate the distance from the present stub to the top of the absent disk. Establishing elevations from existing marks involves use of more than one bench mark as a check, and as material for adjustment, so the slightest discrepancy in a vertical mark can cause trouble.

A quick scan of your most recent four finds leads us to ask for better examples of unclear pictures. These are very good, we think. One thing we try to do that you don't is to position the disk in the lower center of the area shot. That is, near the bottom of the picture on the vertical center line. We use fewer red arrows that way. In one of your bridge abutment shots, an extra several inches of whiskbroom work would have made the disk stand out all by itself. But as we said, these look pretty good to us. Cheers,

The following url provides a window in which you can enter a single PID and discover what project or projects it has been part of. At the moment, for repeated use it seems best to bookmark it, because the back button, at least on Safari, doesn't take us back to the window from a project list. http://www.ngs.noaa.gov/cgi-bin/SURV_ID/mark_sources.prl

Thanks, as always. We'll be on the road soon, guided in part by blank counties on your map. Cheers,

GeorgeL-- Thank you, thank you! It is so good to have that settled.

GeorgeL and jlw--- About three years ago, we came across the term “Triangulation Diagram 6460” in the data sheet for SY2315, then designated “Tacoma Lincoln High School Flagpole.” We had also encountered it in the data sheet for SY2916, DEF, about 7.6 miles to the northwest near the tip of Point Defiance. What connection would there be between this tantalizing document and the ones you’re discussing? Many thanks.

Actually, they often do compare notes, but it is not at all unusual for a state's highway or transportation dept. to have a geodetic section, with responsibility for setting marks, and for deciding which of those marks will be established according to the rigorous standards of NGS, and which will not. So it is not uncommon to find, in the NGS database, marks that were set by a state highway department. But a great many more of the state's marks will not be in the NGS database. Advanced Google search "Nebraska Department of Roads" (phrase) and "geodetic" (first window), and then go to the site with "dor" in its url. Looking around there might turn up somebody who can help with the mark you are closing in on. Good hunting!