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Bill93

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Everything posted by Bill93

  1. Sorry, I haven't researched this. I was just struck by the irony of what looks like a survey market that says it isn't.
  2. I saw reference to this posting about a former Native American boundary that someone has placed disks along. The unusual feature is that the disks are marked "NOT A SURVEY MARKER." Scroll down in the linked page to find pictures. https://masonellis.wordpress.com/2013/01/20/in-search-of-the-quapaw-line/
  3. True, surveyors no longer adjust compasses for anything but rough recon. Magnetic stations are also used for the study of what's going on inside the earth and to update the charts for aviation, where magnetic compasses are still used. https://www.boldmethod.com/blog/learn-to-fly/aircraft-systems/how-your-magnetic-compass-works/ .
  4. Here is the big discussion of this on the forum a few years ago, with participation by Dave Doyle. What in the world does that mean? I think it means that there are too many iron objects, like water pipes, light poles, cars, concrete rebar, etc. near most of the old magnetic stations.
  5. I have some disagreement with the NGS on diskless stems. I reported a remaining stem from a vertically mounted disk as POOR and they changed it to NF. There was no doubt of the identity and could have given the original elevation within 3 mm, which is good enough to be useful for most non-geodetic purposes. Even a regular horizontally mounted disk that is gone leaving a stem could serve as a check within a cm.
  6. Another "traveling benchmark" that has a lot of logs is JZ0826, but fortunately it hasn't been seen lately. It is officially destroyed on the NGS site.
  7. The one that is buried should NOT be marked destroyed just because it is difficult to access. If it can be exposed with effort and used by a surveyor to obtain an elevation, as the prior logs indicate, it is still a good bench mark.
  8. I logged the traveling disk as destroyed again, but that won't keep people from logging found the next time the guy takes it to an event. Most people would rather log something than understand what it was for. I didn't recognize any regulars from this forum among the incorrect logs.
  9. As, unfortunately, do most in the USA. I think you mean NGS, not USGS, since the list here came from NGS and contains their marks along with a very small fraction of the USGS monuments in the country.
  10. The list available here is a snapshot from about 2000 of the United States National Geodetic Survey list of elevation bench marks, triangulation stations, and intersection stations. In the British-influenced world, trig points correspond to our triangulation stations, and I'm not sure whether they carry elevations.
  11. You might get more traffic if they weren't premium caches.
  12. I know of lots of USGS disks that aren't in the NGS integrated database.
  13. Note that it is a US Geological Survey disk, not Coast and Geodetic Survey or National Geodetic Survey. Only a minority of USGS marks are in the NGS data base. Most of them were not measured to the standards needed for the NGS list, but only to mapping standards. USGS data is available from them on request but they aren't particularly interested in recovery reports.
  14. I find benchmark hunting to be more interesting than finding an green match container in an evergreen tree or a plastic container every 0.1 mile. I like measuring and figuring out what happened between the time a mark was placed along railroad and I get to the location 80+ years later to find a recreation trail or other changes. I like understanding what elevation marks are used for and how triangulation stations were measured. And if you do a good job of accurately logging, it is useful to NGS and professional surveyors to know which marks are still around for use and how to find them quickly after decades of change around them.
  15. I agree with Calloway that his coordinates are most likely. He pointed out to me that my alternate coords, with technicalities most people won't care to figure out, are the third most likely scenario. The second most likely is a local scaling about some project point that would give answers so close to the first method that the difference won't show up on a recreational GPS.
  16. https://forums.geocaching.com/GC/index.php?/topic/305887-statistics-are-on-vacation/ Holograph worked hard to keep the stats up to date monthly but circumstances overtook him 6 years ago and he stopped. I expect he will probably read this thread because he has logged in recently. His web site didn't come up for me.
  17. The measurements are supposed to be horizontal. The fact that the re-measurement found them shorter would be consistent with the first numbers being slope distance with modest changes in elevation (1.72 and 1.42 m). 6.5 cm in 22.78 m sounds like too much to be due to inadequate tension on a sagging tape, which if the difference were smaller would be another likely problem. But I'd have expected a C&GS crew to avoid both those problems.
  18. Interesting. It would indeed make sense for those stubs to be left from some tower. However, I doubt it was the triangulation crew's tower. In 1951 when this mark was set, US C&GS was using Bilby towers, which were a triangular inner tower for the instrument and a triangular outer tower for the crews. A single square tower is something else. And it doesn't seem right that any triangulation tower would have been built so far off center from the disk, since the instrument had to be over the disk. The stubs aren't mentioned until the 3rd entry on the data sheet, 1966, so I'm guessing there was a tower for some other purpose there sometime between 1951 and 1966. The data sheet says the leg distances are: KU2634'THE STATION MARK IS A STANDARD DISK STAMPED BETH 1951 SET IN THE KU2634'TOP OF A 12-INCH SQUARE CONCRETE MONUMENT PROJECTING 1 INCH ABOVE KU2634'THE GROUND. IT IS 11.2 FEET NORTHEAST OF THE SOUTHWEST ANGLE IRON KU2634'ANCHOR STUB, 10.6 FEET NORTH-NORTHWEST OF THE SOUTHEAST ANCHOR KU2634'STUB, 8.3 FEET SOUTHEAST OF THE NORTHWEST ANCHOR STUB, 6.9 FEET KU2634'WEST-SOUTHWEST OF THE NORTHEAST ANCHOR STUB, I don't think 10 meters is right. From the data sheet distances, the side of the almost-square is about 12.8 ft (3.9 meters) and the mark is 2.48 ft from center. Your pictures can be linked from your geocaching recovery report for KU2634, as this one of a stub
  19. And in case you aren't familiar with converting to DD mm.mmm format, from Callaway's post I calculate N38 20.534 W0 81 39.940 That should get you in the neighborhood. Since the surveyor didn't give you the "metadata" that tells what his numbers mean, there's a bit of uncertainty. He was probably working in NAD83, and your handheld (unless newer ones have improved the conversion) is in WGS84 even if you tell it you want NAD83, so there's a meter or two difference there. And the biggie is whether those coordinates are true state plane. Since state plane is near the elevation of the ellipsoid model of the earth, and there is distortion in flattening a piece of earth to a plane map, distances between two points on the surface are usually longer than the difference in state plane coordinates. To band-aid this and allow people to work in ground distances, some people scale the SPC values to get coordinates in ground distances. When they do this, they need to specify exactly what scaling was used so that others can follow the process, but this isn't always made clear. IF this was done to the coordinates you have, they could be off 200 ft. In that case try N38 20 31.520 W081 39 58.786 (N38 20.525 W081 39.980). On Google Earth, the first coordinates are between the NW corner of a parking lot and the house to its WNW. The second set are SSW of that house toward the road.
  20. From the way submissions have been edited in the last year or so, I'd guess either a different person is handling them or new internal guidelines are in play for that person. I favor the new person theory, because some of the edits look to me like the person is not as familiar with the subject matter as one would be after years of doing it..
  21. I certainly want the latest data sheet version, but in a few cases the historical one has also helped me, so I'd hate to see those go away. Besides adding new recoveries and later datum tags, NGS has sometimes taken things off the data sheet, particularly where there was some mixup, and I have found that historical info useful in understanding what happened.
  22. I am also a bit surprised this effort was done during the war. I can't think of a strategic reason they needed good lat/lon in the area at that specific time, and would have expected manpower to be directed at more urgent tasks. The COLTON RESET data sheet is at https://www.ngs.noaa.gov/cgi-bin/ds_mark.prl?PidBox=MC1496, just in case someone wants to see it without going through the search. It says the reset disk was placed over the underground mark after the original surface mark position was disturbed. Even though it is in the same place to the best of their ability, they bothered to make a new designation because there might be some small error. It has been measured by GPS so has an elevation, which the old one did not. The original COLTON is AJ1659 in case you are interested in the original description, which isn't the same as the newer one. You can't make a pidbox link to it, but can see the data sheet by searching by PID with the "destroyed" box checked. The lat/lon are truncated to scaled precision for NAD83, although they must have originally been to adjusted precision in NAD27 as shown in the superseded data on the reset data sheet. That PID is probably a newer assignment than the reset one, but I thought the PIDs were assigned before 1981, so am a bit confused why the data sheet looks like it was made after the reset. By comparing descriptions, it appears the present driveway was built around the mark sometime between 1943 and 1981, as the old description has it "in the front yard". Edit: I notice the geocaching page has the original OLD description with the MC1496 PID and does not mention that it is a reset. A cacher has pasted in the new description with his log. The "Original data sheet" captured by Geocaching on the logging page for MC1496 has the old description and superseded adjusted NAD27 coordinates. This confirms that NGS went back and split the old and new into separate PIDs sometime after 2000.
  23. Probably someone read a faint, smudged, or sloppy 9, or low-quality copy, and took the 9 as a 7. The AZ coordinates were probably scaled like those for elevation marks, and if 71 degrees hit a road at 1.8 miles, those coordinates got entered. Most AZ, reference marks, and temporary bench marks (TBM) have a PID (often starting with B or C) that isn't "published." If you look them up, though, they do have approximate coordinates and a notation that they have no geodetic quality data. DSWORLD seems to access those values. Occasionally you will find one of those marks was measured to the tight standards and has a "real" PID and data sheet, but that is not common.
  24. Delta East Base https://www.geocaching.com/mark/details.aspx?PID=MC1516 https://www.ngs.noaa.gov/cgi-bin/ds_mark.prl?PidBox=mc1516 Delta West Base https://www.geocaching.com/mark/details.aspx?PID=MC1521 https://www.ngs.noaa.gov/cgi-bin/ds_mark.prl?PidBox=mc1521 They are about 14.56 km (9.04 mi) apart.
  25. Kayakbird might find something of interest in this post from another forum, that I found while searching for something to put in another thread. https://rplstoday.com/community/surveying-geomatics/mr-penry/
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