curvature versus slope
  n = 1775618 
  X=0, Y = 22.57 +/- 19.35 
  Weighted least-squares fit:  Y = 43.8 + 2.551 X  + -0.02667 X**2 

slope versus dZ, curvature < 5
  n = 89912 
  X=0, Y = 5.63 +/- 4.56 
  Weighted least-squares fit:  Y = 6.7 + 0.265 X  + -0.00058 X**2 
     at X = 100, Y = 27.4 
     effective RMSE xy = 41.7 

slope versus dZ, curvature < 15
  n = 262773 
  X=0, Y = 5.63 +/- 4.56 
  Weighted least-squares fit:  Y = 7.5 + 0.305 X  + -0.00020 X**2 

curvature versus dZ, slope < 10
  n = 72540 
  X=0, Y = 7.71 +/- 5.41 
  Weighted least-squares fit:  Y = 7.6 + 1.432 X  + 0.03082 X**2 


Number of samples 1811317
Max dz = 900
Mean dz = 42
RMS dz = 65.9696900099
100cm = 88.8209518268 percentile value of dz