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Balls, you say?

On my way into work, I go over an unremarkable steel bridge. This morning, perched on the bridge’s railing, were two small white spheres like the ones in the picture. Surreal.

So I looked around and found a man in a Highways Agency van and gave him my best “what gives?” face. He held up a contraption on a tripod and said, “do you know what this is?” A theodolite, I guessed.

Not exactly. It was a 3D laser scanner and he was scanning the bridge. He had no idea why; probably for some maintenance purpose.

The spheres are a reference point. The way he explained it, the spheres can be seen from a long way off. The software knows to look for a white sphere, knows they are spheres and so can calculate the exact center as a precise reference point.

His ones were magnetic (no tripod), so he could stick them on the bridge where he liked. And very odd it looked, too. I wish I’d taken a picture, but my phone was in an inner pocket.

This site, owned by a scanning service, explains how to use multiple reference spheres to survey a large building in chunks. In their example, you use six spheres. All six spheres must be visible in each shot, but you can only move three of them at a time between images. In the end, the software can cut together an accurate picture from aligning all the references.

If you want to know more, useful search terms are “Laser Scanner Reference Sphere” or “White Sphere Scanning” (I got a lot of stupid 3D models of spheres before I found the right words).


Comment from BJM
Time: February 10, 2022, 8:13 pm

I swear Stoaty, you always have the most interesting shit going on! Country life in the UK is a lot more interesting than the rural US.

Comment from durnedyankee
Time: February 10, 2022, 8:15 pm

I read about Thodolite.

He was King of Four-door right? heir to the throne of Hatchback before he was deposed by Chevron.

Seriously, ain’t the idea of using a sphere to calculate the exact center an awesome idea? Science can be really cool.

Comment from S. Weasel
Time: February 10, 2022, 9:25 pm

We have a saying, BJM, that if you wait long enough, everything comes to our little village. We had the Vulcan flyover, the Red Arrows, the circus. There’s a classic car show that goes right by our door. A couple of film crews came past us daily to film at the beach.

Durned, I have no idea how the word ‘theodolite’ popped into my head – and how it was actually the word I wanted – but the Highway Agency man didn’t seem impressed.

Comment from Armybrat
Time: February 11, 2022, 12:50 am

Many years ago I ran a motion analysis lab. We used fixed cameras placed along a “runway” to record the movement of reflective markers along the runway. We also had several embedded force plates along the runway. Knowing the height of the cameras, the distance from the “runway”, the length of the runway and force displacement along the runway, we were able to calculate very precise movement trajectories and deviations. A bit of knowledge of human anatomy and biomechanics (almost like I was a PT!) and you could really map out a specific treatment plan.
This sounds a lot like what I used to do…only in the non-human subject world.

Comment from durnedyankee
Time: February 11, 2022, 4:29 am

@Sweasy – that very word came up in valid conversation a mere week ago with my “I’m a geophysicist! NOT a geologist! ” friend when we were talking about marking the boundaries of our place in East Texas.

Me, I just stomp around (Bomba! Umseeqwe! Bring the flamethrower! This underbrush is hell!) until I find bits of fence, him, he says we need a theodolite. This is what happens when you hang around with people who know what they’re doing, as opposed to me.

Comment from Some Prisoner
Time: February 11, 2022, 3:29 pm

I have had an irrational (?) fear of large white spheres found in unexpected places ever since watching the TV show

The Prisoner

years ago…

Comment from Deborah HH
Time: February 12, 2022, 3:24 am

@durnedyankee—This was at Maggie’s Farm today.
onX mapping is a hunting app, but it might be useful in determining your land boundaries.


Comment from durnedyankee
Time: February 12, 2022, 1:51 pm

@Deborah HH – Awesome! Thankyou! While the acreage we own has three easily discernable boundaries, on the North (county road), East (county road) and West (Sam Houston’s first barbwire fence), the South side has some lovely wood that I long to make lumber out of, but won’t because I don’t want to cut down someone else’s trees. I’ve got it down to around 5 feet of the line using a compass and the survey plat, which is NOT helped by the fact that the old fence line on that side doesn’t seem to parallel the actual boundary for some reason.

Comment from ruralcounsel
Time: February 14, 2022, 12:35 am

Just getting the target coordinates for the future artillery or mortar barrage.

Comment from BJM
Time: February 18, 2022, 3:36 am

@durned…before we built fences we had a survey done and our boundaries were way off the plat map. Get herself a metal detector and scan for the monuments.

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