Land Surveying 101 - Tripod Selection
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- Опубліковано 6 сер 2024
- How much does a tripod affect the total station measurement? Does temperature change play a roll? What about fastener tension? In this video we explore all of these questions using a science based approach.
00:00 - Intro
01:53 - ISO 12858-2
03:38 - The Vienna Tests
04:22 - Height Stability
06:22 - Vienna Torsional Rigidity Test
08:36 - Horizontal Drift
11:00 - Influences From Temperature
14:12 - Tribrachs
15:10 - Affects of Fastener Tension
17:51 - Final Thoughts - Наука та технологія
You’re on fire with these high quality investigations 🔥
I simply CAN't wait for the next video! Your content is out of this world!
Another awesome video with so much great information and in depth explanations! Great work once again! Thank you for your work!
Your videos are great. Keep them coming!
Great study on tripods...you see so many tripods poorly set up, cheap tripod legs, poor quality tribrachs and can only imagine the consequential error especially with robotic measurement so thank you for such an in depth and well documented study.
You are the best. Thank you for other valuable information for surveyors.
I've been surveying for about 18 years, and I've used both Leica GST 120-9 Tripods, Crain Trimax Tripods, and Dutch Hill Tripods.. I wasn't really a fan of the trimax tripods, I liked the large top plate, they felt very solid, but we had a lot of issues with the foot pegs splitting over time and use. I liked the Dutch hills they seemed to be decent, but for some reason I always came back to the Leica Tripods
Sounds weird but I'm a fan of the twist clamps.. a lot of the guys I worked with didn't like the Leica legs even though they came with the instruments... they said they looked cheap. I never understood why, they always felt solid to me. They may not look very complex but they seemed to be of great quality and well thought out. My favorite feature being the interlocking foot pegs for easy transport and storage, no additional straps to corral the legs together, just a simple but very effective tripod in my opinion.
@@aidanburfield2670 +1 for the interlocking foot design. So simple yet so effective. I’m actually surprised in all this time another company hasn’t “borrowed” that idea.
This white paper was released by Leica who made a summary...biased? certainly. when they say "temperature and humididy were not considered" they definitively controlled it...humidity, the achiles heel of wooden tripods...I also remember reading the paper a while back and seing the tripods were tested fully extended. Who the heck uses the tripod like that? Also, using a torque wrench? Why not just tighten them firmly? With the torque wrench Ithey can tighten the leicas just enough and leave the others a bit loose...
On the other end, your recommendations to minimize the error brought by the tripods are really good! Thank for your videos!
Well the white paper was actually based on a study that was done years before. Absolutely temp and pressure were controlled, which makes sense to me to control external influences that would affect the results to make sure all testing done was fair. I actually don't believe the tripods were fully extended. It says in the study they were lengthened to ISO spec. ISO gives very specific specs to which the tripod should be setup at during testing which they complied to. Why use a torque wrench? Again, to make sure all test subjects were tightened equally. It's just good science. Now... did Leica cherry pick data from that study to make their tripods look better or did they have influence on what tripods were in the test? It is possible. If I could afford to replicate such testing with the controls they have in place and the instrumentation & access to equipment, nothing would make me happier to be able to provide unbiased test. But as far as testing parameter's I believe they were following ISO's standards for the most part. Hopefully I can revisit this topic again in the not so distant future when I have more resources available. Thanks for the comment!
Awesome work! Keep it up
Great video. Still, I'd have liked to see at least one of the cheaper but heavy weight tripods (eg/Topcon/Sokkia) included in your testing. The Leica white paper on tripods skipped that also.
The Leica White paper did skip other tripods, the study the white paper was based off of actually did include a cheaper Chinese Fiberglass tripod. I didn't include it in my review because I could only find an abbreviated version of the original study and didn't have all the graphs of the actual measurements. It performed similar to the Trimax except the horizontal drift was almost 3x worse than the Trimax and obviously magnitudes worse than the Leica's.
I wish I had access to a larger variety of equipment for my own testing.
If any equipment suppliers happen to read this and want to team up together for future videos, please reach out!
Most of the setups I see now are too narrow at the base, because of the methodology most people now use to set up. Most people now, at some point in their process, look thru the optical plummet when the tripod is only approximately level, and while holding two legs not touching the ground. Correct setup process should instead involve looking through the optical plummet ONLY after all three legs are at their final location and planted. With all three legs planted and the tripod head roughly eyeball level, a plumb bob (or just a good eye) can be used to get the tripod head within 30mm (0.10') by lengthening or shortening one or two legs. The instrument is then leveled perfectly, and slid over the point. The optical plummet is NOT (or rather should not be) utilized until the legs are all planted, and the instrument is completely level. This process does require using a plumb bob (or just a good eyeball) to get the instrument within 30mm in the first place. Why is this important? Because first, the method most people use nowadays involves a "dance" where you place one leg, level the tripod head roughly, and then, with the other two legs held off the ground, and while looking through the not really plumb yet optical plummet, you attempt to get the tripod head roughly over the point using the plummet. You then lower the two free legs, plant all three legs, and then again look thru the still not plumb plummet to figure out which tripod legs to lengthen or shorten. This "dance" results in "narrow" setups that can easily be blown over, and I have seen that happen. The "dance" also causes instrument setups to take way too long, although that is rarely important. I can set up my instrument in sixty seconds, with a wide stable stance, 19 times out of 20. The main reason I don't like the "dance" method most folks use now is not because it is slow, but because the setups don't look stable to me at all. In my opinion, those narrow stance setups contribute a lot to the torque, settlement and other problems mentioned in this video. They are possibly the greatest contributor to such problems, with the exception of folks who try to use the truly lightweight tripods for the heaviest robots. If you don't do anything else, use a heavy wood tripod, and lengthen those legs about a half foot on every setup. There is NO advantage to those narrow setups, and no good reason to use them.
hysteresis is pronounced he-stir-esus not hi-stir-sus
Right you are, thanks for the heads up!