curvature versus slope
  n = 532081 
  X=0, Y = 7.31 +/- 3.33 
  Weighted least-squares fit:  Y = 7.2 + 0.599 X  + 0.01141 X**2 

slope versus dZ, curvature < 5
  n = 359751 
  X=0, Y = 10.08 +/- 6.40 
  Weighted least-squares fit:  Y = 9.9 + 0.062 X  + -0.00058 X**2 
     at X = 100, Y = 10.2 
     effective RMSE xy = 4.2 

slope versus dZ, curvature < 15
  n = 504531 
  X=0, Y = 10.66 +/- 6.72 
  Weighted least-squares fit:  Y = 10.6 + 0.069 X  + 0.00010 X**2 

curvature versus dZ, slope < 10
  n = 444614 
  X=0, Y = 9.36 +/- 5.96 
  Weighted least-squares fit:  Y = 9.2 + 1.588 X  + 0.02702 X**2 


Number of samples 532083
Max dz = 72
Mean dz = 9
RMS dz = 11.5325625947
100cm = 0 percentile value of dz