curvature versus slope
  n = 242750 
  X=0, Y = 43.71 +/- 34.75 
  Weighted least-squares fit:  Y = 75.8 + 0.990 X  + -0.00988 X**2 

slope versus dZ, curvature < 5
  n = 6458 

  Weighted least-squares fit:  Y = 101.4 + -0.398 X  + 0.00372 X**2 
     at X = 100, Y = 98.8 
     Bad fit. P2 = 0
slope versus dZ, curvature < 15
  n = 21438 

  Weighted least-squares fit:  Y = 98.4 + -0.362 X  + 0.00354 X**2 

curvature versus dZ, slope < 10
  n = 1993 
  X=0, Y = 104.01 +/- 20.49 
  Weighted least-squares fit:  Y = 103.4 + -6.905 X  + 0.51569 X**2 


Number of samples 246102
Max dz = 900
Mean dz = 94
RMS dz = 127.910124697
100cm = 61.557403028 percentile value of dz
Mean dz (curv<=5) = 88
RMS dz (curv<=5) = 102.542674044