curvature versus slope
  n = 309898 
  X=0, Y = 11.83 +/- 10.27 
  Weighted least-squares fit:  Y = 23.7 + 3.781 X  + -0.04239 X**2 

slope versus dZ, curvature < 5
  n = 132899 
  X=0, Y = 9.87 +/- 5.88 
  Weighted least-squares fit:  Y = 9.5 + 0.292 X  + 0.00105 X**2 
     at X = 100, Y = 49.2 
     effective RMSE xy = 75.8 

slope versus dZ, curvature < 15
  n = 176584 
  X=0, Y = 10.05 +/- 5.78 
  Weighted least-squares fit:  Y = 9.2 + 0.358 X  + 0.00127 X**2 

curvature versus dZ, slope < 10
  n = 132767 
  X=0, Y = 10.92 +/- 5.86 
  Weighted least-squares fit:  Y = 9.8 + 1.477 X  + 0.05671 X**2 


Number of samples 312801
Max dz = 900
Mean dz = 33
RMS dz = 67.5721836261
100cm = 91.7481082222 percentile value of dz