curvature versus slope
  n = 1063234 
  X=0, Y = 8.99 +/- 6.67 
  Weighted least-squares fit:  Y = 8.4 + 1.912 X  + -0.01369 X**2 

slope versus dZ, curvature < 5
  n = 90073 
  X=0, Y = 8.44 +/- 7.44 
  Weighted least-squares fit:  Y = 16.7 + -0.186 X  + 0.00141 X**2 
     at X = 100, Y = 12.2 
     Bad fit. P2 = 0
slope versus dZ, curvature < 15
  n = 256780 
  X=0, Y = 6.80 +/- 5.46 
  Weighted least-squares fit:  Y = 15.7 + -0.250 X  + 0.00358 X**2 

curvature versus dZ, slope < 10
  n = 457760 
  X=0, Y = 19.36 +/- 14.97 
  Weighted least-squares fit:  Y = 15.9 + -0.367 X  + 0.00629 X**2 


Number of samples 1063451
Max dz = 800
Mean dz = 11
RMS dz = 62.7136348811
100cm = 99.7918098718 percentile value of dz
Mean dz (curv<=5) = 11
RMS dz (curv<=5) = 79.5801482783