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Everything posted by jwahl

  1. There must be a way to adapt one of those relatively inexpensive laser levelers that are sold in hardware stores for quick alinement of picture frames and the like for under $100. I see a few in the $20 range and several in the $30-$35 range. These things are not always super precise and the visible range and pattern of the laser might be considerations. Set it up on some kind of stake, level it. Read the line on a vertical rule on each end and subtract the foreward point from the back point readings to get the change in elevation. - jlw
  2. jwahl

    Heavy Metal

    The only thing I can think of off hand is that they had some idea that there might be construction or similar activity on the peak and they wanted to try to increase the chances that some marks would survive. What I notice is that about half of them are unusually far away for RM's and that could be the reason.
  3. I thought I would add a strong vote for reporting postions on Azimuth marks. The stations themselves may seem like they are somewhat obsolete, but having used many of them in my own ancient surveying career, I still like the idea. Finding an azimuth mark was often hard because no distance was usually given to them. There are probably still some occasions where any info would help preserve them even though perhaps they are not used as much as in the past. To me getting a position on one is really a value added thing, just like for scaled marks. They are technically part of the station. The whole issue of to what degree monumented marks are useful to surveyors can be pretty esoteric. Yes, today with GPS, a surveyor may not even use nearby marks for horizontal control at all. But not everyone has GPS and it is sometimes still nice to have a check. Vertical control is a whole other thing. Hopefully if you find an AZ mark you get a position and it can go into the report. Heck someday all those GPS birds might fall out of the sky and terrestrial surveying may come back into vogue. Who knows! jlw
  4. Since someone else verified it DSWORLD has had that truncate to the nearest second since inception. That is not too useful to have every station misplotted. So glad it is fixed but am irritated that it was that way to begin with. Wrote my own program. However I cannot test any new version of DSWORLD since the setup.exe wants to update files on my machine, without telling me what. To tell the truth that type of install behaviour makes me pretty nervous. I haven't had any trouble installing any other windows applications. It harkens back to the day when everyone's apps install their own DLL's and that is fine for them but then 5 other apps quit working. - jlw
  5. One use schema I can imagine is that these are used to evaluate whether conditions are safe for a prescribed burn. That would be a go or no-go evaluation. I can also imagine that during fire season the 'stick's' could be put down on their little stand most of the time. When a reading is desired, someone picks them up, weighs them on the scale, enters it into a log like other weather measurements and then puts the sticks back onto their ground stand. Nothing to keep you from doing that every hour if you wanted to.
  6. Here it is at Forestry Supply Fuel Moisture Scale Forestry Supply Catalog Shown in box on page 49 of this pdf Instruments Manual - jlw
  7. My guess is that it is probably a device for measuring the moisture content of wood (duff and fuels) used in assessing fire danger. So not exactly air humidity, but similar. - jlw
  8. On the second example, the mark is the GLO iron post and cap section corner. It looks to be in pretty good condition and probably suitable for vertical benchmark. From what I can see in the picture it looks vertical and does not appear to have been disturbed. Those posts are about 36 ins. long and are flanged at the bottom as well as filled with concrete.
  9. And ECC commonly stands for an Eccentric Station. Those were often used because the main station could not be occupied, or to place targets or lights. It is somewhat possible that the True station was marked with the PK nail, however to know you would have to find the COE record and description for the station somewhere. - jlw
  10. Many Federal agencies perform surveys for either boundary or engineering purposes. In the course of that, particularly if GPS is involved, they may set control points to use as GPS RTK bases or other purposes. I would call them project control. I suspect this is one such point. These are seldom submitted to NGS and would not usually have any RM's or Azimuth marks. You may be able to find information by contacting the USFS office in the area, or the Regional USFS office. They often have a regional surveyor who may keep records, and there are sometimes forest surveyors. Similar monuments might exist for F&WS, BLM, NPS and COE, even Bureau of Reclamation at one time did a lot of surveying for projects. Besides Federal agencies you might expect to find monumented project control points for state agencies like DNR's or even on private surveys. State DOT's more often submit their work to NGS than other agencies but not always. I did a lot of conventional control (pre GPS) by traverse in BLM, mostly for photo control and we set monuments all over the west. We even did a bit of control using a pre-GPS system called Transit Doppler which was only good to a meter or so at best. I would not be surprised if records of many of the stations I set have been lost track of over the years since they are often kept with a particular office or project and eventually archived or disposed of. That doesn't make me happy either. - jlw
  11. Not to get into a surveying debate on the benchmarkers forum, but... It is true that today with GPS the surveyor can get accurate horizontal coordinates almost anywhere using CORS for L1 or OPUS for L1/L2 equipment. However there are still parts of the country that do not have a dense population of CORS stations. That means that long occupations are the rule (at least 2 and maybe 44 or more hours may be needed to bring in control). On the other hand for vertical control it is my opinion that the accuracy of GPS is not only less, but to get orthometric heights requires good geoid modeling, and if the CORS stations are 10-50 miles away and there are not too many high order stations in the area. that can be questionable. So the existent nearby 1st of 2nd order monumented vertical station(s) are still the standard which should be at least checked into if not used as the primary control. Thus today in the age of wonderful GPS, the traditional published vertical benchmark is probably as important as ever. Now that is not so for third order stuff which may not even have elevation in the current vertical datum. Also, there is often a need to know the historical datum that was used for the local infrastructure. It doesn't do any good to precisely know the ellipsoid elevation or even the orthometric elevation in the lastest datum if the sewer system was designed and built based upon a city datum who you can best recover from those old benchmarks. Everything is relative some times. jlw
  12. Those water horizontal drill things they use all the time now to put in fiber optic lines do considerable vertical displacement. They came down my street and messed up a lot of driveways and gutter. Even tapping off into a house was the same. Any BM would be unreliable after they came through.
  13. It used to be that there was a requirement to preserve marks, or notify if it was inevitable to be destroyed on DOT type plans for new work and notice to contractors. Knowing the marks were there was required. I would bet that is no longer done. I see crews out now that probably have no idea there are marks there. I know a few marks near me are likely destroyed by new highway contstruction, fence construction, and the new thing is putting in fiber infrastructure underground. Too many people out there with backhoes and such.
  14. Similar comment. What we called 'heat waves' limit visibility over long lines. If you're in mountainous country where your line of sight may be some distance above the ground you may be able to see large target sights up to 12 miles or so, but where lines of sight are along the ground it is hard to see or to get accurate angles. Generally the air settles down a few hour into the night and one will get much better results under those type of conditions. I would bet that 95% of all C&GS (NGS) work was done at night to lights set over the station. Usually on whatever stand or tower was erected there for the instrument when occupied. Some data sheets note the height of the light, and some note an eccentric light in rare cases. A light right on the station mark might have been done for a short site such as to an azimuth mark. There are quite a few pictures on the NGS site. You will also find lots of instructions on lights and so forth in various C&GS publications and Manuals on triangulation.
  15. The Waymarking site probably has several categories that include various kinds of marks all over the place. For a while about 98% of the marks being posted in the Public Land Survey Waymarking group were actually markers in the UK.
  16. That last pic is the center rod on what used to be a standard size "ignition cell". Those are about 8 ins. tall and 3.5-3 in. diameter and were used for starting model airplane glo-plug engines. I used them to power a home phone system and dozens of other experiments when I was a kid. They were 1.55 volt single cells, but I also remember they were packaged into a 4 cell format in one tin enclosure about a foot long with a handle and were used in electric fence chargers. That would have been a form readily available in hardware stores between 1940 and 1990. Ignition cell example However these are faked up but that's what they looked like mostly. and here, looks like these might still be for sale. Ignition "6" cells Almost any station that had a light for a signal would have had batteries to run them. The NGS picture is a perfect example. There is also a larger dimension lantern battery, horizontally with screw posts and the large reflector light screwed right onto the battery. 1231 Lantern Battery Note that spec sheet says it contained 2 rows of 4 "F" sized cells. I suspect that the regular lantern battery cells are thus "F" sized. I have never heard that one before. More research. I find a lot of "F" sized rechargeables referred to as "long D" in some ads. This link, if you get it to work, shows a page that lists D F and G sized carbon zinc cells before the "6" which I think is the ignition cell. No pictures though. Carbon Zinc types LED's would have been great if they existed then. One more link about "F" cells. Note that the size 6 pictured is not a typical type. The real ignition cell has a single large carbon post about 3/4 in. diameter and 6.5 in. long. as shown in the previous post. Because these types are no longer readily available, people are faking up replicas with all kinds of internals. Apparently the "6" sized was also used in old phone systems inside the crank wall phone boxes. I can vaguely recall from my grandmothers house on the farm. More Note to self: interesting how many of these types which were once ubiquitous, are now long gone from the market. PS I remember that the long lantern battery format similar to the 1231 came in either a 6 volt (parallel 2 rows of 4 cells in series) or 12 volt (all in series) apparently a type 732. All the "Lantern" types are still sold today. <Nostalgia alert off.>
  17. Due to some bizarre myth, there are a lot of videos on youtube which dissect 6 volt lantern batteries. They show that it contains 4 cells (not surprising) about the diameter of a D cell, perhaps larger, and longer. So I still say what you found is consistent. This saves us from having to repeat the exercise. This is one of them: - jlw
  18. Part I. I would suspect AZ Marks with RM's would be rare. Occasionally when a station is lost, or for other site reasons and RM or AZ Mark is used as a station itself. In that case for an Azimuth mark it would make sense to set RM's to it. It might have just been considered a nice monument to use as a station in a later survey and thus elevate it's status. Part II. I think your idea about battery posts is the most likely, there are or have been all kinds of battery sizes. For example the 4 cells inside a 6v lantern battery might be longer than D cells, but I would not expect them to have the little cap. - jerry
  19. I suspect the wire was to fasten some kind of target pole alongside the concrete post. I think these observation stations are probably for defomation monitoring. - jlw
  20. Well a tripod is a temporary struture to set up survey instrumentation usually over a permanently monumented point. I think these pillars are a permanently monumented point designed to facilitate installation of an instrument. It is just that some of them were probably established for a particular project or purpose and may not be in the NGS database. Some may be. - jlw
  21. I may not have this all correct, but that is called a trivet plate. Another device not that different than a tribrach screw down to it with it's leveling feet in the grooves, an instrument mount is on the upper part of the trivet. There must be pictures of trivets around the net somewhere. I found a few. These type posts are often set where their is going to be some kind of regular monitoring. One I used was near a future dam site. - jlw Kern Trivet adapters Also notice the "pillar plate" at the bottom of the page. Warren Knight Trivet at bottom of page Brunson Trivet I have no idea if those are typical or not and they may be most adapters. My vision is that some instruments have bases that go directly on the trivet.
  22. It could be mark GU2091, although there are a number of discrepencies with the datasheet. There is one DNF for it and the elevation does not match, but it has a similar designation. 21 M vs the mark M 21, perhaps part of a series.
  23. jwahl


    Although probably not significant, there is a nearby mystery station PY0678 P 9 In the current NGS database. Perhaps some preliminary reference to data not yet published? Sure looks like a vertical monument to me, but a bit likely to be damaged. - jlw
  24. It looks as they have pilfered or misunderstood a story from someone who legitimately recovered a magnetic station in a cemetary. All the lore about it having magnetic properties is hogwash. Note the recent recovery by Penry Mag Station Wayne and http://www.penryfamily.com/surveying/stantonmag.html It would appear that most of this story has entered the realm of rumor or folklore perhaps generated by third parties retelling or embellishing the story. There are also stones set to mark true meridians in some parts of the country which were set in the mid 1800's to allow surveyors to determine the magnetic declination of their compasses. Those were set in pairs to mark a North and South end, and usually had no association with C&GS. In both cases it would be counter productive to the purpose of the monument(s) if there were any significant local magnetic disturbance or anomaly. The last thing we need is to popularize the idea of digging around for monuments in cemetaries by the general public based on such whims. - jlw
  25. From that last picture, I would say he had no fear of heights! - jlw
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