curvature versus slope
  n = 492512 
  X=0, Y = 13.83 +/- 11.32 
  Weighted least-squares fit:  Y = 24.1 + 3.684 X  + -0.04129 X**2 

slope versus dZ, curvature < 5
  n = 160398 
  X=0, Y = 8.50 +/- 5.00 
  Weighted least-squares fit:  Y = 7.5 + 0.389 X  + 0.00135 X**2 
     at X = 100, Y = 59.8 
     effective RMSE xy = 93.2 

slope versus dZ, curvature < 15
  n = 273415 
  X=0, Y = 8.30 +/- 4.85 
  Weighted least-squares fit:  Y = 7.7 + 0.447 X  + 0.00086 X**2 

curvature versus dZ, slope < 10
  n = 151317 
  X=0, Y = 9.28 +/- 5.06 
  Weighted least-squares fit:  Y = 8.2 + 2.077 X  + 0.05046 X**2 


Number of samples 496240
Max dz = 900
Mean dz = 30
RMS dz = 72.4844810977
100cm = 93.814686442 percentile value of dz