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Resection procedure in the modern era
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Strictly speaking I believe that resection refers to the classical angle only procedure, whereas free stationing includes the distance observation. In modern usage resection has become synonymous with free stationing. At least that’s how I see it.
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As long as you understand the limitations, a 2-point resection can be quite helpful, even at the start of a project. Be sure to actually store and record the description of the points used so that future translations include that data. (The old Geodimeter software would use the measurements to generate the station location, but wouldn’t store the points. )
Using 2 points hold that line, and averages the error from record to measured… so it can be helpful if you are working with parallel lines and offsets.
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As our equipment improves, so do our habits and provedures. I see a LOT of construction staking done with a single two-point resection and no hard check to a third point or the item being tied into. A real time saver (not).
I will admit most of my solutions in the last 15 years have been two point, as a third will only confirm my error estimates. You still make the standard checks before staking improvements.
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I used to say that resections (the type that includes distance measurements) were OK as long as I was doing them. Company policy was to not use them. It seemed to be beyond the capabilities of the field crews, and they (the field crews) were happy with that, for the most part. Early attempts had been failures.
I now use them routinely and expect my people to as well. Control is set in places that are not necessarily convenient for setting up on, but safe from destruction and accessible for resectioning. My rule is to always use at least 3 points in the resection. The only exception is for a little quick and dirty used to stake out and find more control. Use 3 points. Typically the last of the 3 is also used for a check shot, and the 1st is tied at the end for a closing out check. Truly -if you are going to resect to 2 and check to a 3rd, why not just resect to 3?
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I used to say that resections (the type that includes distance measurements) were OK as long as I was doing them. Company policy was to not use them. It seemed to be beyond the capabilities of the field crews, and they (the field crews) were happy with that, for the most part. Early attempts had been failures.
I now use them routinely and expect my people to as well. Control is set in places that are not necessarily convenient for setting up on, but safer from destruction and accessible for resectioning. My rule is to always use at least 3 points in the resection. The only exception is for a little quick and dirty used to stake out and find more control. Use 3 points. Typically the last of the 3 is also used for a check shot, and the 1st is tied at the end for a closing out check. Truly -if you are going to resect to 2 and check to a 3rd, why not just resect to 3?
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Any resection can be valuable when used appropriately.
I often do a 2 point resection on points from an old survey that quickly tells me if the points I found are what I think they are and where to look for other points.
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