Plat Plotter has a Calculate Curve Table feature that generates a sequence of points for use in drawing plot lines. To put another way, it converts a curve into several short, straight segments approximating the curve.
thence South 13°0'00" West 201.05 feet to the beginning of a tangent
180.00 foot radius curve, concave Northwesterly; thence Southerly and Westerly along the arc of said curve through an angle of 98° a
distance of 307.87 feet; thence tangent to said curve North 69°00'00"
West 255.0 feet to the West line of the Northeast Quarter of the
Southeast Quarter of said Section 5;
For this example, the straight lines before and after the arc are entered as:
S 13 W 201.05 and N 69 W 255.00
The Calculate Curve Table feature will create a sequence of values that can be placed between the above two entries given a Chord & Radius.
How does one get from the:
to the beginning of a tangent 180.00 foot radius curve, concave
Northwesterly; thence Southerly and Westerly along the arc of said
curve through an angle of 98° a distance of 307.87 feet; thence
tangent to said curve
to the Chord and Radius values needed by Plat Plotter?
The Chord for Plat Plotter is an angle which will be "S" ddmmss "W" in this case and length fff.ff feet. I assume that the Radius can be taken directly from this legal description, 180.
Chord: S ddmmss W fff.ff
Radius: 180
So, more specifically, how to calculate ddmmss and fff.ff?
Best Answer
The legal description is giving you a delta angle of the curve, the radius, and the distance traveled along the curve.
Simple Curve Formula:
R = Radius L = Length of Curve D = Degree of Curve T = Tangent Long Chord = LC
From your data you have a 180 ft radius curve that has a 98 degree delta angle since the bearing entering the curve is 98 degrees less than the bearing exiting the curve.
Long Chord = 2R sin 1/2 Delta so:
(2*180) (sin 49)
360 * 0.754710 = 271.695449 feet.
I hope this helps.