For elevating a SX station to scan, it doesn’t need to be level. But it does need to be stable. If it isn’t stable enough, it will give you an error and won’t scan.
Going to test it this weekend. So far, when scanning with the SX12, we've only been able to use quality timber tripods, even brand name fiberglass moves and sets off the alarm, which is set at 8 arcseconds, got my fingers crossed. All the joints are adjustable to remove clearance and it feels solid, but we just won't know until we test it.
For fun read the NGS pub or see if they might have the class online now. River and valley crossings. It was for optical leveling to transfer geodetic leveling across rivers and valleys. It is a bunch of hidden information in how they do what they do curvature and refraction especially.
Billl. That guy I mentioned above who is still at NGS helped build that one. If I remember the story correctly he had his son there as well. His son is a PE now. He was much younger then lol. He is a great guy him and his wife both. He said he enjoyed being part of that very much.
At the dedication.ceremony there was a Mr. Jones who worked on the crews back when they were still moving towers around for triangulation. I think that pretty much ended in the early 1970's.
This old guy in his 80's climbed the tower unaided and with no gear the day of the ceremony. (OSHA, what's that?)
I once recovered a triangulation station out in a field by some fairly long measurements from reference marks. When I looked at my pictures later I realized I missed picking up a souvenir Bilby tower bolt that had been in the hole.
Yeah. That’s what this guy from NGS said. Back then they had no harness or safety belts. Just climb and do what needed to be done.
Those old marks are exciting to find. The thought of doing what they did and accomplished is amazing with the equipment. Now we can never leave the office and ties every CORS together across the country. I was doing some work at a naval facility which has an old NGS mon which was not called NGS then. They built a look out tower over it and it’s still accessible but I was trying to tie it with gps but couldn’t. It is a mark that has several azimuth to some industry smoke stack features along the Potomac. . I ended up tying to it conventional. I rigged up a long plumb bob and dropped it from the look out tower to transfer the mark up. They had an old digital transit 20” gun laying around. So for fun I went up set up wrapped the angles to my points and all the old azimuth marks the transit was way out but just to get a feel for the historical significance of what they accomplished. Makes me appreciate the technology today most times. However when I see companies that have the technology but still use it like it’s 1980 all the standards and processes to accomplish something it makes me wonder Why am I doing something for 8 hrs when in 2 hours I can get the same results and same quality. Doesn’t make since to my brain.
This presentation is interesting, on the NGS site, I only see the optical theodolite method, but this presentation mentions approval of an edm total station method also:
https://docplayer.net/63170299-Ngs-river-valley-crossing-procedures.html#download_tab_content
I will have to make a phone call. See if they have the edm one out yet. I will have to take out the trash and do extra honey do’s to get on the wife’s good side. The guy who did a lot of work on that use to borrow my trailer once in a while to fetch hay for his horses. Great guy. I honestly haven’t met anyone I disliked from NGS including the wife. lol. They are a great group of folks and honestly all want to provide us with the best they can.
Hey I got kudos for telling you about that presentation. The wife loves when she gets to hear from outside the agency that surveyors are reading and such the products they put out. I am very blessed she is a good woman and hard worker. I think that must be a Trimble S9 in that presentation. Which on the optical side is rare at NGS historically.
@OleManRiver 👍😀<div>
Thinking about making a couple of prism holders that can be installed in the main shaft of the tripod, so they sit directly under the centre trunnion axis of the total station. A slight variation on methodology, but same principle.
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I never cease to be amazed at the ability of humans to come up with clever ways to solve problems. Cool looking bit of kit.
Man you are innovative. That’s what it is all about. Seeing a problem making a solution and test and verification of that solution. Keep it up. I think you get it all worked out you should patten that.
You mention the error tolerance displayed at the end of a scan. That is just how far out of level the instrument got during the scan. It’s not a measure of stability of the scan. If the tripod isn’t stable enough, it won’t even scan. This is because the instrument vibrates a bit while scanning and when warning up to scan.
