5J-17.052 Minimum Technical Standards: Specific Survey, Map, and Report Requirements
(b) Boundary Monuments:
7. Side ties to locate or set monuments shall be substantiated by a redundancy of measurements.
The office wishes to interpret this as locating each corner from two different traverse points. Opinions vary among the field crews as how to do this. Do we set a traverse point close to another traverse point if necessary? The geometry would stink. I say set a point on a traverse line and locate a corner a second time from there. What would you do?
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Mark,?ÿ
You are a survey field tech working for the county. Ultimately the decision is up to the PLS in your office on how to interpret the MTS. Not you or your field crews decision.
7. Side ties to locate or set monuments shall be substantiated by a redundancy of measurements.
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That sounds pretty wide open. Does the Florida board MTS have a positional tolerance for monuments ?
Hot take: with modern equipment and proper procedures locating a point from two control points in the same control network, or from a POL set on a traverse line, offers no more "substantiation" than just locating it twice (independently - break down, re-level, new backsight) from the same point.?ÿ
You're ?ÿlooking for a blunder; ?ÿif you locate a point twice from the same control network (even if once from control and once from a fly hanging out there with no check) and you get more than a couple of hundredths difference, you've got bigger problems. ?ÿ
I would think you could just flop the scope and double the angle, shoot the distance again. As James mentioned, the possible problem is a blunder because it's not in the control loop.?ÿ Although I can't think of how you screw up a sideshot with modern technology, I suppose it's possible due to human error/mistake.?ÿ
I would think you could just flop the scope and double the angle, shoot the distance again. As James mentioned, the possible problem is a blunder because it's not in the control loop.?ÿ Although I can't think of how you screw up a sideshot with modern technology, I suppose it's possible due to human error/mistake.?ÿ
The easiest way for my guys to screw up (blunder) a sideshot with modern technology is using a mini prism with a different offset for the sideshot and not changing it in the collector.?ÿ
Does the Florida board MTS have a positional tolerance for monuments ?
I haven't found anything concerning that yet.
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The field crews were just discussing how to do what the PLS wants. If we set a "secondary" traverse point close to a "primary" traverse point just to locate a property corner from a second point, then your're destroying the geometry of the traverse. Just a discussion. Thanks for replying!
Hot take: with modern equipment and proper procedures locating a point from two control points in the same control network, or from a POL set on a traverse line, offers no more "substantiation" than just locating it twice (independently - break down, re-level, new backsight) from the same point.?ÿ
You're ?ÿlooking for a blunder; ?ÿif you locate a point twice from the same control network (even if once from control and once from a fly hanging out there with no check) and you get more than a couple of hundredths difference, you've got bigger problems. ?ÿ
Maybe the PLS wants to do use a bearing-bearing intersection. Maybe the PLS is uncomfortable adjusting the traverse and then adjusting the side shots. Sometimes I think a PLS, being a leader, should discuss his opinion with the field crews. Discussions benefit everyone. Thanks for replying!
If we set a "secondary" traverse point close to a "primary" traverse point just to locate a property corner from a second point, then your're destroying the geometry of the traverse.
I'm not sure worry about the geometry is warranted when you are measuring both angle and distance every time.
Geometry is critical when you do a bearing-bearing intersection or a distance-distance intersection, but bearing and distance complement each other to make a strong determination.
A simple direct and reverse shot would provide "redundancy of measurements", but there are two more statically robust ways to do this, assuming you just can't shoot the side shot from two of your normal traverse points.?ÿ
The best way is to set two traverse points close together and traverse completely through both of them and shoot the side shot (direct and reverse of course) from both of them.
If you want to save time you can simply shoot it using both the backsite behind you and the foresite ahead of you as backsites.
The first method works well if you are using least squares.
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I'm not sure worry about the geometry is warranted when you are measuring both angle and distance every time.
Geometry is critical when you do a bearing-bearing intersection or a distance-distance intersection, but bearing and distance complement each other to make a strong determination.
I think my use of "primary" and "secondary" traverse points is confusing. There would only be one traverse (control loop). I never knew that a bearing-distance intersection is strongest. Is that true in all cases? Thanks for replying!
One bearing and one distance from different points is also sensitive to geometry. Then 90 degrees is bad.
But if you have both B/D from one point the target is boxed in, sideways within the uncertainty of that bearing and near-far within the uncertainty of the distance measurement.?ÿ A second B/D measurement then gives you nice redundancy.
The reason B/B or D/D intersections don't like shallow angles can be seen by sketching the layout with some uncertainty lines around each measurement.?ÿ If at a shallow angle, the region between the uncertainty lines can be quite long.
I ask my IMan to double the angles between setup points and double the angles to all monuments when a sideshot.
A crew or IMan that complains about the time it takes to do so does not understand their job. Their job is to collect information exactly how the licensed surveyor asks them.
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The only thing that bothers me is setting two traverse points close together. If the two traverse points are 50' apart, I could be taking a 50' backsight for a 500' foresight.
The only thing that bothers me is setting two traverse points close together. If the two traverse points are 50' apart, I could be taking a 50' backsight for a 500' foresight.
No, the back site for each of the two traverse points is the the same.
Instead of setting one foresite and moving forward you set two foresites close together. Then you move up to the first one, backsite?ÿ your last occupied point, shoot the side shot, and shoot foward to the the next point in the traverse. Next, move the instrument over to the nearby point and do the same thing. After moving up, when you continue the traverse , you will shoot the next point by backsiting both the close traverse points.?ÿ
It can mean observations from two different setups, or more traditionally, measuring direct and reverse angles.?ÿ I recall one company I worked for claimed that if they measured down the two side lot lines, then simply taped the distance between the two rear monuments that was good enough... I didn't work there for very long!?ÿ?ÿ
It's open for the licensed professional to implement as they see fit.?ÿ ?ÿ When I was a solo operator, I preferred to observe boundary markers from two setups, instead of leapfrogging a backsight tripod around.?ÿ But that's not always practical, either... so my answer is "It Depends".?ÿ?ÿ
https://www.flrules.org/gateway/ChapterHome.asp?Chapter=5J-17
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Link to the latest version of 5J 17?ÿ ?ÿ ?ÿI searched for "redundancy" and found nothing.?ÿ What am I missing here??ÿ?ÿ
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No, the back site for each of the two traverse points is the the same.
Instead of setting one foresite and moving forward you set two foresites close together. Then you move up to the first one, backsite?ÿ your last occupied point, shoot the side shot, and shoot foward to the the next point in the traverse. Next, move the instrument over to the nearby point and do the same thing. After moving up, when you continue the traverse , you will shoot the next point by backsiting both the close traverse points.?ÿ
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I remember doing just that in Alaska!?ÿ Saved a lot of leg work in the woods and tundra.?ÿ?ÿ
