I'm Glad We Cleared That Up
Not too sure?
Nobody tried surveying???
For curves I want to know four things: radius of the curve, arc length, chord length and chord bearing. They do not tell you if the length provided is the chord length or the arc length. On a large radius the two numbers are very similar but a few hundredths here and there add up over a long route survey.
My experience is that if I construct the ends of a curve using a chord bearing and distance, the computed radius and delta will not be the exact numbers (or proper second) they are intended to be, so I have always gone through the radius point, going 400.00 feet (in my example and assuming a tangent curve or where a radial bearing is given for non-tangent), use the labeled delta (left or right) then then back the 400.00 to the EC. The integrity of the numbers remain intact that way.
That's the way I handle curve data - I will use chord information as a check, but nothing more, if I have supplementary data. Draw the entry/exit tangents and fillet with the record radius, check the delta and arc length first before looking at chord info.
Nowadays I label the radial bearings at all curve PC/PTs on my plats, even if the curve is tangent. Gives the next guy a check on tangency, and an easy way to calculate/check the radius point.
They should make this website a requirement for the degree seeking students that need to experience the many and more or less correct ways you can lay out curves etc.
Man I love this site!
NC requires chord bearing and distance so I add it below R and L. In the Boone, NC area it seemed as though PLSs discovered horizontal curves in the 60s and 70s.
Like most people, I'm drawn to symmetry like a moth to flame, but other than aesthetics, I don't see that tangent (or non-tangent) curves are a great improvement in many cases. There's beauty in simplicity.