curvature versus slope
  n = 688244 
  X=0, Y = 11.10 +/- 8.97 
  Weighted least-squares fit:  Y = 17.6 + 4.342 X  + -0.05023 X**2 

slope versus dZ, curvature < 5
  n = 308176 
  X=0, Y = 7.64 +/- 7.32 
  Weighted least-squares fit:  Y = 8.5 + 0.488 X  + -0.00004 X**2 
     at X = 100, Y = 56.9 
     effective RMSE xy = 88.4 

slope versus dZ, curvature < 15
  n = 476114 
  X=0, Y = 8.08 +/- 7.51 
  Weighted least-squares fit:  Y = 9.3 + 0.503 X  + 0.00004 X**2 

curvature versus dZ, slope < 10
  n = 300618 
  X=0, Y = 10.11 +/- 7.38 
  Weighted least-squares fit:  Y = 9.9 + 2.179 X  + 0.02887 X**2 


Number of samples 703139
Max dz = 900
Mean dz = 23
RMS dz = 44.9666543118
100cm = 96.0015018368 percentile value of dz