curvature versus slope
  n = 205555 
  X=0, Y = 9.94 +/- 10.68 
  Weighted least-squares fit:  Y = 36.9 + 3.330 X  + -0.03577 X**2 

slope versus dZ, curvature < 5
  n = 78950 
  X=0, Y = 7.44 +/- 4.24 
  Weighted least-squares fit:  Y = 8.7 + 0.211 X  + -0.00055 X**2 
     at X = 100, Y = 24.4 
     effective RMSE xy = 35.7 

slope versus dZ, curvature < 15
  n = 103679 
  X=0, Y = 7.44 +/- 4.24 
  Weighted least-squares fit:  Y = 8.9 + 0.247 X  + 0.00018 X**2 

curvature versus dZ, slope < 10
  n = 75671 
  X=0, Y = 8.94 +/- 4.90 
  Weighted least-squares fit:  Y = 8.5 + 1.770 X  + -0.13743 X**2 


Number of samples 208655
Max dz = 900
Mean dz = 24
RMS dz = 48.5180378828
100cm = 96.3724808895 percentile value of dz