curvature versus slope
  n = 414779 
  X=0, Y = 14.53 +/- 14.33 
  Weighted least-squares fit:  Y = 28.8 + 3.738 X  + -0.04306 X**2 

slope versus dZ, curvature < 5
  n = 253085 
  X=0, Y = 3.10 +/- 3.57 
  Weighted least-squares fit:  Y = 16.5 + 0.575 X  + 0.00028 X**2 
     at X = 100, Y = 76.8 
     effective RMSE xy = 117.8 

slope versus dZ, curvature < 15
  n = 295849 
  X=0, Y = 3.14 +/- 3.60 
  Weighted least-squares fit:  Y = 16.2 + 0.687 X  + 0.00007 X**2 

curvature versus dZ, slope < 10
  n = 215984 
  X=0, Y = 18.74 +/- 16.14 
  Weighted least-squares fit:  Y = 19.2 + 3.923 X  + -0.02195 X**2 


Number of samples 425275
Max dz = 900
Mean dz = 43
RMS dz = 92.2984290224
100cm = 89.1905237787 percentile value of dz
Mean dz (curv<=5) = 17
RMS dz (curv<=5) = 30.6267856622