I would like any suggestions on how to do this with a tape. (This is pretty non controversial, right?) I have spent a career trying to figure out how to measure things, and I am curious. From the comments in this group, the problems I mention below must have been solved.
First you stretch the tape along the side of the pool. That would work well, but how are you sure you are aligned with the walls, or that the walls are square? Also, you need to measure in several lanes, rather than the side.
So you get in the pool and hold the tape against the walls, 1 foot below water level. The problem is that the tape sags, and any measurement will overestimate the length of the pool by a significant amount. You could pull the tape tighter, but I suspect before the tape gets tight enough, your tape will stretch or break. (I used to assign that as an intro physics problem). I suppose you could build a support structure across the pool, but that would be a pain in the neck, and you would have to move it from lane to lane.
Getting the water out of the pool would make that support structure easier, but the water weighs a lot. It almost certainly causes the walls to bend outward, especially in the deeper pools. (How do the people who design above ground, temporary competition pools do it?) I don't know how much the walls will move, but how do you account for that? (and by the way, how do the masons make sure their plaster/tiling is correct in an empty pool?)
Here is an idea - you lower the water level by a foot or so, and build a *floating* support structure for the tape. I think that would solve most of the problems. Has anyone done that?
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Former Member
Originally posted by Mark in MD
I wonder if someone will eventually come up with a method of measuring pools using GPS. With the technology getting more precise, could it be only matter of time? Just a thought . . . nothing more!
1. GPS dpesn't work indoors.
2. GPS is not more accurate then what was discussed here.
With a handheld GPS, even withthe selective availablity turned off few years ago, the $200 dollar handheld units are only good to +/- 1 meter.
Wanna het down to a few centimeters, you need about $ 40,000 worth of equipement, and it's even more difficult to use than the tape, and it has more quirks and restrictions than a laser.
Yeah, High precision GPS is something I use frequently and do a lot of measurement analisys and adjustments (GPS, and others). GPS would not be the method of choice for this.
It issue is not the technology. Thechnology to measure the pools accurately and precisely exists. It's how it's being used that introduces the errors in the measurements.
Originally posted by Mark in MD
I wonder if someone will eventually come up with a method of measuring pools using GPS. With the technology getting more precise, could it be only matter of time? Just a thought . . . nothing more!
1. GPS dpesn't work indoors.
2. GPS is not more accurate then what was discussed here.
With a handheld GPS, even withthe selective availablity turned off few years ago, the $200 dollar handheld units are only good to +/- 1 meter.
Wanna het down to a few centimeters, you need about $ 40,000 worth of equipement, and it's even more difficult to use than the tape, and it has more quirks and restrictions than a laser.
Yeah, High precision GPS is something I use frequently and do a lot of measurement analisys and adjustments (GPS, and others). GPS would not be the method of choice for this.
It issue is not the technology. Thechnology to measure the pools accurately and precisely exists. It's how it's being used that introduces the errors in the measurements.
