For those days when we need to take some “knowns” and compute the “unknowns”.
In my first week working with a field crew, I learned there is a lot more geometric information to understand about an arc than just its radius and arc length. There is the delta angle, chord distance, external secant, mid ordinate distance and more.
What is even more important is that knowing a couple of those values and a few mathematical equations, you can compute the rest. Having said this, doing the math by hand is not a trivial undertaking. (at least for me)
Fortunately for us, Civil 3D includes a curve calculator where we can enter the parameters we know about the arc and it will automatically compute all of the parameters we don’t.
This can be an extremely helpful tool especially when working with paper documents. Sometimes one or several measurements may be missing. Other times, one or several of the measurements my seem or actually be incorrect.
Having a tool that we can use to reverse engineer missing arc information or simply verify the accuracy of what we were provided can save us a ton of time as well as deliver some peace of mind.
Check out the video below to see how it works.
-Jerry
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