curvature versus slope
  n = 36701 
  X=0, Y = 18.34 +/- 15.04 
  Weighted least-squares fit:  Y = 14.1 + 1.861 X  + -0.01240 X**2 

slope versus dZ, curvature < 5
  n = 952 

  Weighted least-squares fit:  Y = 8.6 + 0.111 X  + -0.00138 X**2 
     at X = 100, Y = 5.9 
     Bad fit. P2 = 0
slope versus dZ, curvature < 15
  n = 3445 

  Weighted least-squares fit:  Y = 9.7 + 0.017 X  + 0.00019 X**2 

curvature versus dZ, slope < 10
  n = 7572 
  X=0, Y = 12.45 +/- 7.19 
  Weighted least-squares fit:  Y = 10.4 + 0.005 X  + -0.00029 X**2 


Number of samples 36865
Max dz = 600
Mean dz = 13
RMS dz = 21.1423745119
100cm = 99.498168995 percentile value of dz
Mean dz (curv<=5) = 9
RMS dz (curv<=5) = 11.313708499