Fig. 4
From: The shape of watersheds

Likelihood contour plot of Hack’s parameters for eight classes of GC. Colour scale gives the likelihood obtained for each pair of parameters. Green and blue diamond show c coefficient and n exponent as defined by Hack2 (c ~ 15; n = 0.6) and Montgomery and Dietrich11 (c = 2.02; n = 0.49), respectively. Grey zones correspond to the parameters space that does not satisfy Euclidean geometry and is discarded from our analysis