curvature versus slope
  n = 551704 
  X=0, Y = 10.50 +/- 8.91 
  Weighted least-squares fit:  Y = 11.7 + 4.855 X  + -0.05814 X**2 

slope versus dZ, curvature < 5
  n = 333482 
  X=0, Y = 10.24 +/- 8.57 
  Weighted least-squares fit:  Y = 7.1 + 0.689 X  + -0.00025 X**2 
     at X = 100, Y = 73.5 
     effective RMSE xy = 114.9 

slope versus dZ, curvature < 15
  n = 477169 
  X=0, Y = 10.97 +/- 8.89 
  Weighted least-squares fit:  Y = 7.3 + 0.741 X  + -0.00107 X**2 

curvature versus dZ, slope < 10
  n = 349354 
  X=0, Y = 10.66 +/- 8.05 
  Weighted least-squares fit:  Y = 10.2 + 1.669 X  + 0.05436 X**2 


Number of samples 559317
Max dz = 900
Mean dz = 16
RMS dz = 34.5832329316
100cm = 98.5101471974 percentile value of dz