curvature versus slope
  n = 700144 
  X=0, Y = 6.98 +/- 5.09 
  Weighted least-squares fit:  Y = 6.3 + 3.109 X  + 0.00457 X**2 

slope versus dZ, curvature < 5
  n = 379227 
  X=0, Y = 16.77 +/- 11.04 
  Weighted least-squares fit:  Y = 13.7 + 0.611 X  + 0.00009 X**2 
     at X = 100, Y = 75.7 
     effective RMSE xy = 117.0 

slope versus dZ, curvature < 15
  n = 611532 
  X=0, Y = 16.74 +/- 10.86 
  Weighted least-squares fit:  Y = 13.3 + 0.670 X  + -0.00082 X**2 

curvature versus dZ, slope < 10
  n = 530945 
  X=0, Y = 17.18 +/- 10.41 
  Weighted least-squares fit:  Y = 16.7 + 0.173 X  + 0.15583 X**2 


Number of samples 701617
Max dz = 900
Mean dz = 16
RMS dz = 21.9089023002
100cm = 99.7495784737 percentile value of dz