or 'elbows,' named based on the concavity at the extrema. For the remainder of this text, we will refer to these points as knees. Points of high curvature, or possible knees, are shown as plateaus in the difference curves in Fig. . In Fig. , y-values of the normalized curve correspond to potential 𝜖 values, and so we find the y-values of the normalized curve at the x-value of extrema of the difference curves. To calculate 𝜖 values for a unique distribution of distances, we use the Kneedle algorithm , a general approach to 'online' and 'offline' knee detection. The online method searches through the whole array to find the global extrema, whereas the offline method returns the first extrema. To find the point of maximum curvature, we use the Kneedle method in the online mode to find the global extremum of a polynomially fit curve (to reduce the effect of noise). This global extremum corresponds to the default 𝜖 calculated by HiMap, shown as the y-value where the black dotted line on Fig. , right, intersects the normalized curve.