curvature versus slope
  n = 2996979 
  X=0, Y = 7.38 +/- 4.47 
  Weighted least-squares fit:  Y = 6.1 + 4.660 X  + -0.05207 X**2 

slope versus dZ, curvature < 5
  n = 1726658 
  X=0, Y = 9.58 +/- 6.26 
  Weighted least-squares fit:  Y = 13.9 + 0.461 X  + 0.00043 X**2 
     at X = 100, Y = 64.4 
     effective RMSE xy = 98.8 

slope versus dZ, curvature < 15
  n = 2664929 
  X=0, Y = 9.72 +/- 6.38 
  Weighted least-squares fit:  Y = 13.6 + 0.581 X  + -0.00096 X**2 

curvature versus dZ, slope < 10
  n = 2326909 
  X=0, Y = 16.05 +/- 9.46 
  Weighted least-squares fit:  Y = 15.7 + 1.648 X  + -0.07263 X**2 


Number of samples 3039809
Max dz = 900
Mean dz = 18
RMS dz = 28.5131548588
100cm = 98.4347042857 percentile value of dz