A. Reverse curve is always plotted on extended radius of former curve. Radius does not have to be of the same length.

B. Tangent curve is always plotted from a radius drawn at 90° from ending. If curve is concave (curving over) to southwest, radial line is drawn southwesterly; if concave to northeast, radial line is drawn towards northeast, etc. Central angle determines length of arc (curve) since it is difficult to measure around a curve with a ruler.

C. Non-tangent curve description ma y give the angle of the radial line pass-through the ending point of the last course — this line being the bearing of the radius of the non-tangent curve; or the description may give the bearing of a line passing through the ending point of the last course to which the curve would be tangent. The radius would then be drawn at 90° from this bearing.

Compound curve is figured along the same radial line, but each curve has a radius of a different length.

D. When plotting street and highway descriptions, curves sometimes double back on themselves. Description will read "to a point of cusp, thence along a curve," etc.