curvature versus slope
  n = 1121032 
  X=0, Y = 44.76 +/- 31.56 
  Weighted least-squares fit:  Y = 70.7 + 1.220 X  + -0.01345 X**2 

slope versus dZ, curvature < 5
  n = 41445 

  Weighted least-squares fit:  Y = 74.4 + -0.092 X  + 0.00091 X**2 
     at X = 100, Y = 74.3 
     Bad fit. P2 = 0
slope versus dZ, curvature < 15
  n = 152127 

  Weighted least-squares fit:  Y = 77.2 + -0.119 X  + 0.00141 X**2 

curvature versus dZ, slope < 10
  n = 7625 
  X=0, Y = 65.64 +/- 13.49 
  Weighted least-squares fit:  Y = 68.6 + 2.681 X  + -0.04655 X**2 


Number of samples 1125195
Max dz = 900
Mean dz = 83
RMS dz = 108.323589305
100cm = 69.1497029404 percentile value of dz
Mean dz (curv<=5) = 65
RMS dz (curv<=5) = 78.5748051223