In the context of circular curve elements, what is the point of curve?

The point of curve refers specifically to the location along a circular curve where the curve begins. This is a crucial element in circular curve geometry, often denoted by the acronym "PC" (point of curvature). It marks the transition from a straight alignment (the tangent) to the curve itself. Understanding this concept is fundamental for designing roads and railways, as it helps in determining how vehicles will enter the curve.

The midpoint of the curve is not the point of curve; rather, it’s simply a point situated directly in the center of the curve. The end of the curve, while it is a separate and specific location, is identified as the point of tangency (PT), which is distinct from the point of curve. Similarly, the point where the curve ends again refers to the end of the arc, which is not the point of curve, but rather the start of the next tangent section. Knowledge of these points enables geodetic engineers to accurately plan transitions in alignment for safe and effective transportation infrastructure.