Papa-Bear-NYC

No they don't have to be .prl. If you use NGS>>GPS, .txt is just fine. I will often download a single datasheet that got missed or updated since a major download, and NGS>>GPS is happy with the one, and GSAK hapilly updates just that one station. For that matter I don't use FTP to get the bulk of them. I have GSAK databases by county, and seldom exceed the limit using the regular datasheet site (HERE). For big counties, when there's more than 2000 or something like that, I just do it half at a time. If you do a whole state at a time, I guess my method would break down. Someone else will have to supply the FTP URL as I never use it.

One of mine from early June finally showed up yesterday. Horray! And a Lazarus Log at that. I'm working up a post on a historic mark and I was waiting for the log to get into the NGS database, so watch for it in a day or two.

The benchmark list is fixed. You can log a recovery (= found it) of one in the list, but you can't add a new one to the list. This situation is explained here: Benchmarks not in database To log a recovery, or even a non-recovery (looked but couldn't find it) go to the page for the benchmark and click on "Log This Benchmark" under the word "Navigation" in the upper right of the screen.

From your descriptions, those are Tidal Benchmarks. Although only a subset of Tidal Benchmarks are NGS stations and thus on this site, you can find them on another NOAA web site: NOAA Tides and Currents Navigating from that, (In left Side Bar, Under Bench Mark Data Sheets, click on Present Epoch > Massachusetts) I found a tidal station (No. 8448558) in Edgartown, which in fact list a No. 9 and No. 11. Check this: Edgartown Tidal station. The descriptions should match where you found these marks. There's also a No. 6 listed (on the First National Bank - go find it!). None have a PID, and thus none are in the NGS data base or on this site. You can be the first to Waymark them if you choose. Make sure you have good pictures, preferably one showing the area, and another a closeup in which you can read the stamping, and a good GPS reading for each.

That's two months in a row with no reports, yes?

And I added a "Lazarus Log" which I hope makes it in. A very historic marker - stayed tuned ...

Those flat disks were out of use by about 1919. The station "Bald Hill" is also described in Special Publication No. 76 "Triangulation in Massachusstts" Bald Hill (Essex County, Town Boundary Survey, 1916). On the summit of a hill of the same name. 2 1/4 miles to the northeastward of Beverlv and 1 mile northward from Beverly Rock. ’The station is 21 meters (89 feet) north of a wall running northeastward over the hill and is marked according to note 2, with the inscription "Bald Hill 1848.” A reference mark, note 12a, is 5.05 meters (16.57 feet) southwest of tho station. The position of this station can probably be obtained from the Massachusetts Commission on Waterways and Public Lands. Note 2.- A standard disk station mark wedged in a drill hole in outcropping bedrock Note l2.- A standard disk referenco mark with the arrow pointing toward the station, (a) wedged in a drill holo in outcroping bedrock This tells me that the history is something like the following: 1) A station called Bald Hill was set in 1848, probably a drill hole set by the CGS 2) In 1916, as part of a town boundary survey, the "standard disk" was placed in the original drill hole, with the date 1848 indicating the date for the original station plus an RM disk set 5.05 m southwest of the station. These would both be UC&GS flat type disks. 3) In 1937 MGS took their turn and set RM2 and RM3 4) In 1954 a new station disk was set as quoted in the 1981 log. 5) In 1981, another new disk and new RMs were set The old 1916 disk was apparently left around to be found by the metal detector guy. The original RM1 was probably also one of the 1909-1919 flat disks.

No, not really - you can still get to it on the NGS website by doing a PID search. I believe. No the problem is not getting the datasheet - you can always get destroyed mark datasheets - the problem is, the NGS deleted all the entries after 1932, which contained a wealth of interesting history. In fact the first entry after the destroyed one (also from 1932) explained why it wasn't really destroyed. And they didn't do it long ago, they did it sometime after 2006, when I recovered the mark shown in the picture. The NGS datasheet was still full in 2006. Compare the copy of the datasheet saved on GC.com with what's left on the NGS site.

Slight correction: azimuths are given in the format dddmmss.s where the seconds may be omitted. Thus RM2 is at azimuth 41 deg 48 min.

A monel rivet has a bit of copper in it so there can ba a greenish or yellowish sheen. Here's a few really close close-ups: KU0899 KU0903 KU0905 This one is cool since it's the northernmost bench mark in Manhattan KU0915 Yes, these were along an active RR. Don't do it!

Not to shot a hole in your sails but often times its not professionals looking for them. It may say USGS, NGS but often times its the new guy who gets to do this kind of work. Our boss would always tell us to let the seasonal/temp workers do those jobs, we need you to do the more important work and not ride around all day looking for BM's etc. Granted even though these guys were student engineers and student surveyors they sometimes could not tell their rear end from a hole in the ground. All college and no knowledge = a supervisor. What you say is undoubtedly true today. But the one I was thinking of was this 1916 station in Vermont: QH0564 The "Not Found" was by the International Boundary Commission (which maintains US-Canada boundary) in 1971 (55 years later). There were good reasons they couldn't find it (read the report and you'll see) and I highly doubt they used summer interns given their perennial low budget which has to be approved by both countries. Now-a-days they would probably hire an outside contractor (or more likely simple not bother looking for such marks) and your observation would probably be correct.

Sorry John, but I don't agree, because the map you are looking at was produced in the 1980s or 1990s on NAD83. In 1959 they used 15" series maps (or in Az maybe 15" x 30") built on NAD27. I've looked at many of them (historic maps of New England) and they are 1) 1:62,500 scale (vs. 1:24,000 scale) and most that I've seen don't have many of the benchmarks on them. To make your point I'd like to see the 1959 version of the map of the area. The closest you could come is by zooming out on MyTopo, and you'll see that when the map switches to the higher scale, the benchmark does not appear on the map. Note also from the 1934 description "NOTE-- DISTANCES IN DESCRIPTION DID NOT SEEM TO FIT WELL WITH TOPOGRAPHY AND OTHER PORTIONS OF DESCRIPTION. B.M. IS PROBABLY STILL IN PLACE." This tells me the original description on file was probably messed up. This is likely what the USGS had to look at (not on-line data sheets as we have today). Since the mark is scaled, it was put on the map from the description when the map was produced in the 1980s. Looks like they were lucky to use the part of the description that fit, not the part that didn't. So I would say for me "missing the point", that the jury is still out.

The is one big difference between finding a marker today and finding it in 1959 - your GPS. The 1934 local ties (rock ledge, small canyon, etc.) are all fairly generic. BTW: the marks was set in 1934 by CGS, not USGS. I have also found markers that professionals missed years ago. I could not have found them without my GPS and metal detector. (GPS being by far the more important tool).

I would say there is an abandoned road in the 1941 photo that meanders basically southward, but in the 1951 photo it curves slightly to the west and then disappears in what may be a cultivated field to the south of the main road. The straight line heading west in the 1951 photo may be a property fence line rather that a road. There's an indication of that in the 1941 photo as well. I suggest you use the position given in the Google map and look for the mark in those current day trees shown in the street view. This is probably close to where the east west tangent crosses the old road. Note that the first portion of that old road is roughly the same in both photos. You could also try to use the direction "70 feet from the center line of the highway" where I would say that would be from about the middle of the curve in the road. I assume that's almost exactly the line used in the street view, but it gives one more cross check since the error in the street view of the distance along the line of site is probably greater than in the bearing of the line of site. Here's the 1951 photo where I put a little red circle to show what I mean:

Nice one. And there looks like a line scribed along the south edge of the east-west portion which is your tangent. And that road looks very crisp as if it were just built. Maybe those traverse stations A, B and C were for the road survey. That photo plus the street view I linked to should make your life easy. OTOH, that photo shows a fairly rough undeveloped area with a few little ponds or depressions, whereas now you have trees and a nice lawn, so don't get your hopes too high. Looks like a bulldozer or two have been over that land. If you're lucky they may have just buried it.

Well you have something going for you - it's a horizontal control station, meaning that the position is accurately determined. (aka it has "adjusted coordinates"). A traverse station is not as accurately determined as a triangulation station, but It's likely still much better than your GPS. A GPS and a metal detector is a good set of tools to start with, but I would try to find old maps or aerial views of the area and try to see if the road has been moved or straightened since the mark was established in 1943. The tangent to the sharp curve and the old abandoned road may be your best clues. Even if the old road is overgrown see if you can tell by the absense of old trees where it might have been. The GPS will get you withing 10-20 feet and from that you may be able to make out from the contours of the land where the abandoned road was. And your station is in the center of that road so you need just search out from the highway sweeping with your metal detector along the presumed path of the old road. Then search and probe and dig. Thanks for the tips... I'll look up a old map of the area from USF's database and go from there... See my last note added to the bottom of my post.

Well you have something going for you - it's a horizontal control station, meaning that the position is accurately determined. (aka it has "adjusted coordinates"). A traverse station is not as accurately determined as a triangulation station, but It's likely still much better than your GPS. A GPS and a metal detector is a good set of tools to start with, but I would try to find old maps or aerial views of the area and try to see if the road has been moved or straightened since the mark was established in 1943. The tangent to the sharp curve and the old abandoned road may be your best clues. Even if the old road is overgrown see if you can tell by the absence of old trees where it might have been. The GPS will get you withing 10-20 feet and from that you may be able to make out from the contours of the land where the abandoned road was. And your station is in the center of that road so you need just search out from the highway sweeping with your metal detector along the presumed path of the old road. However, looking at the Google map tells me the area south and east of the station is a new development so highway (presumably Wesley Chapel Loop) may be a straightened version of the 1943 road. It aligns perfectly with the new development east-west roads, so I would be very suspicious of that. But that line of trees along the west side of the development which aligns with the north-south portion of Wesley Loop may be a property line which preexisted the development, so that might be where the old fence was. And the icon on the Google map (which I would trust) may well be about 14.6 feet from that line. In fact, this street view shows where to look, probably better than your GPS - seldom do you see a picture like this. Go find it, it's right in front of that 2nd tree. :-) Street view of ALO480

1) Go to the NGS DATASHEET RETRIEVAL PAGE http://www.ngs.noaa.gov/cgi-bin/datasheet....Type=DATASHEETS 2) Select the first option "PIDs" 3) you can now enter your list of PIDs in the box, of if you have them in a file on your PC, use the lower section to select your file. In this example I entered 3 in Essex County NJ remember to select an option if desired from the list below that, The only one I ever use is "Include Destroyed Marks." 4) click on "Submit" 5) another page will appear with another list of the PIDs. Click "Select All" and "Get Datasheets" 6) The datasheets will come up. Save them to your PC and you are done.

When you read the full data sheet, you will notice the US Power Squadron marked the station as "Not Found". This is the right status. Why: 1) You know that the existing mark is wrong because of the stamping of the County Engineers. Therefore it's not the mark. For a bench mark (vertical control), you can't just replace a disk, even in the same drill hole because even that operation would invalidate the carefully measured elevation. It's not found unless it's found. 2) so why not "destroyed" instead of "Not Found"? Because you don't know what happened to the old disk or to the bridge. You would have to research and see if it really was rebuilt, if so how? Maybe the old mark is hidden by some new concrete. Or maybe they (and you) were looking at the wrong bridge or the wrong side or whatever. It's only destroyed when the you see them rebuild the bridge and knock the old disk out (and take a picture). I found a station once that was lost for 40 years under a building on a mountain. They removed the building, I came along a few years later, dug down 18" (with a great deal of help from my friend Dave) and we found it. It's not destroyed unless it's destroyed.

Most of the discussion here seems to be about terminology. I think that is NOT where to start. When I look at the data sheet, the first thing I see is it's a horizontal control station, the second thing I see is it's on top of a grain elevator with a "head house" and the station mark is at the center of the elevator. I also note it's a USGS station and it's third order and the setting is a concrete slab. That's the context and the details of the description should be understood in that context. Terminology should come next. Two points are described. What were the function of these two points in the context of the occupation of a horizontal control station? There are not a lot of choices. My best guess it that the "station mark" was not occupied, but was observed, and the "TURN-POINT STATION" was occupied, roughly the opposite of what Z15 said. BTW: As Foxtrot-xray points out, it's called a "TURN-POINT STATION", not a "Turning point". I have not read thousands of data sheets as Z15 has, but hundreds yes, and can't remember seeing the term before for either horizontal OR vertical control. The similarity to certain terms used in leveling is seductive, but in the end, I think, irrelevant. I think if we want to go farther than speculation on this. we need to understand the practices and terminology used in 1966. Compared to today, we know the practices have changed totally. I see people doing jobs along the streets where I live with whom I have often conversed. Typically they would not know a theodolite if it hit them on the head (and that would hurt ) - at least the ones under 50. Has the terminology also changed - you bet it has. Anyone know a retired surveyor who worked on a horizontal control team in the 1960s? Preferably in Texas? This is where George usually comes to the rescue. George?

I would like to point out that AH2323, is a horizontal control station, so a "leveling run" would not be done to or from it. Furthermore, for the life of me I can't imagine how one would level to a point on the top of a grain elevator unless you had a leveling rod 400 ft long! In the context of this situation, I would guess "turning" refers to turning angles, and most likely simply means it's a point where the theodolite was set up to observe other stations. Starting with the azimuth mark (somewhere out there) they would assign that angle 0, then turn first clockwise to the other stations being observed and then do the same counter-clockwise. Often this was repeated a number of times to reduce the average errors. Since there is reference to a "turning point" and a "station mark", this is most likely what is called an "eccentric". An Eccentric was used for observations because of better sight lines, whereas the station mark was further away from the edge closer to the building. The station mark was generally used to observe TO the station (from other stations) and had the flag or heliotrope visible from the other stations. The turning point OTOH, was away from the building ("head house") and was used to observe FROM. The difference was accounted for mathematically in a process called reduction. That's my take on this. Here's a diagram for an early triangulation in NY City. The station is the middle of a tower which was observable from other stations. (see KU3532). But they could not set up an instrument on the roof over the finial, and if they set up over the exact point on the platform under the finial (which they had in fact measured) they could not see the other stations through the narrow windows. So they observed various other stations through the windows. In this case there were 5 eccentrics, positioned near the various windows. Complicated, but that's how it was done. Rg

I modified the least squares calculation to use MY0001 instead of MY3374, and now the result is within about 2 feet of the NAD83 location. So the "bad" control point MY3374 did affect the calculation to the tune of 16 feet of error, as you would expect, but not as much as if it were the unlucky choice of the other methods, which may have resulted in 136 feet of error. When ever I have done this, I always used first order points and tried to make sure the old datum points were in the same survey. For New England, these tended to be in the major CGS surveys done in the 19th century. Ironically, for one point, Watatatick Borden (1834) which an early survey had explicitly said was about 7 feet in a certain direction from Watatick (a "newer" CGS point.), the old points from the early publication using the old datum gave almost exactly the numbers that were found on the ground. OTOH the new adjusted points and the new datum was off in the wrong direction by 3 feet. Lesson: 1) stick to the same survey if possible (obviously not possible here since no modern survey used the Borden point) and 2) using the method for very short distances is generally useless due to the poor "leverage" in the triangulation (actually an "excess" of leverage). But both methods gave a position within 6-10 feet, so I can't complain.

Assuming you can still get to the mark. I've done this method once, did a whole bunch of planning (days), got permission from my railroad to go out and hike down to the mark, finally, after a week of various plotting and knowledge of where rock outcroppings were along my line, I get there only to discover that the month before there was a mudslide in that area and the station was supposedly 10 feet under the slick. Klemmer - if you do go hunting for some of these, be sure to document them and share pictures. I'd be really curious to see these and see if they can be 'rediscovered'. Spoilsport! Come to New England where we don't have mud slides - but maybe a little snow.

I've had good results doing something like you propose and found marks that were otherwise lost. This was my method: 1) Find the "lost" station and a nearby station which is still in the NGS database in the old publication. They will generally give coordinated on the old datum to 2 or 3 decimal places in the seconds. 2) using these old coordinates, run the Inverse program (on the Clarke Spheroid) to find the distance and azimuth from the good station to the lost station. 3) Using these numbers (i.e. distance and azimuth from good to lost), run the Forward program and calculate the position of the lost station from the good station using the adjusted coordinates of the good station on modern datum. Stick these coordinates into you GPS, and go find it. It works. It works, because although the datum change may cause significant changes in the absolute locations, the relative locations (represented by the distance and azimuth between the two stations) changes very little.

Exactly. In theory, and assuming your math is correct, you can get a more accurate position for RM1 or RM2 (which are 'scaled') by computing their position based on the adjusted triang station. (I will add that it's not only triangulation stations that could have this happen, but this is a perfect example.) Now, granted, in examples like this, this would kinda be unnecessary, because you know they're going to be darn close to the main station. However, would something like this be helpful where, say you have a HD_HELD2 station giving reference directions to a SCALED station? Technically - depending on the data given - you could narrow the location of the scaled station down by ~hundred feet, yes? -Mike. Actually, there are some egregious examples I've found. Case in point: Palisades This is an old triangulation station (a bolt) set in 1898 and a first order horizontal station. In 1930 two reference marks were set. Today one of those is (probably) buried under some landscaping and the other one is on a rock ledge about 200 feet south of the station. A few years ago Seventhings and myself measured everything and were well satisfied that every thing was where it should be. So far so good. Then in 1956, the C&GS ran a level line in the area and used both of the reference marks as veritcal stations, i.e. true bench marks. However, when the NGS database was established from the paper records sometime later, instead of using the more accurate coordinates from the triangulation station, they just got out the Topo maps and picked some spots for these two scaled stations. Results: they were far away, and one was actually placed on the wrong side of the George Washington Bridge from where it is actually located. I've seen other similar cases. Cases like this are exactly what your corrections are aimed at, and thank you for taking this issue on.