curvature versus slope
  n = 479677 
  X=0, Y = 50.78 +/- 23.26 
  Weighted least-squares fit:  Y = 60.6 + 1.887 X  + -0.01860 X**2 

slope versus dZ, curvature < 5
  n = 293060 
  X=0, Y = 14.45 +/- 4.39 
  Weighted least-squares fit:  Y = 12.7 + 0.551 X  + -0.00141 X**2 
     at X = 100, Y = 53.7 
     effective RMSE xy = 82.0 

slope versus dZ, curvature < 15
  n = 425929 
  X=0, Y = 17.33 +/- 6.21 
  Weighted least-squares fit:  Y = 13.4 + 0.559 X  + -0.00139 X**2 

curvature versus dZ, slope < 10
  n = 8588 
  X=0, Y = 14.97 +/- 9.08 
  Weighted least-squares fit:  Y = 14.6 + 2.013 X  + 0.02927 X**2 


Number of samples 484072
Max dz = 900
Mean dz = 35
RMS dz = 47.6759897642
100cm = 97.4235237733 percentile value of dz