curvature versus slope
  n = 369688 
  X=0, Y = 9.96 +/- 8.24 
  Weighted least-squares fit:  Y = 14.4 + 4.387 X  + -0.04925 X**2 

slope versus dZ, curvature < 5
  n = 178579 
  X=0, Y = 12.68 +/- 7.03 
  Weighted least-squares fit:  Y = 10.6 + 0.294 X  + 0.00363 X**2 
     at X = 100, Y = 76.3 
     effective RMSE xy = 118.7 

slope versus dZ, curvature < 15
  n = 271017 
  X=0, Y = 13.09 +/- 7.24 
  Weighted least-squares fit:  Y = 10.6 + 0.360 X  + 0.00322 X**2 

curvature versus dZ, slope < 10
  n = 206887 
  X=0, Y = 12.35 +/- 6.68 
  Weighted least-squares fit:  Y = 11.6 + 1.103 X  + 0.09929 X**2 


Number of samples 373271
Max dz = 900
Mean dz = 25
RMS dz = 68.5857127979
100cm = 95.5083571989 percentile value of dz