Profile lines showing crater degradation. We can model the degradation status of craters by changing the parameters in our kernel functions. In simple craters 1 & 2, the solid line represents the original crater, while the dashed line represents the same crater but with a lower (degraded) depth-to-diameter ratio (ratio of solid/dashed line = 0.4/0.1). In fresh craters, we set the degradation vector α = (Δk = −0.3, Δγ = −0.4, Δa = −0.25) (defined in Sect. 3.3). For complex craters, we set the degradation vector α = (Δk = −0.05, Δγ = −0.2, Δa = −0.1).