curvature versus slope
  n = 530206 
  X=0, Y = 43.30 +/- 22.78 
  Weighted least-squares fit:  Y = 50.2 + 2.010 X  + -0.02010 X**2 

slope versus dZ, curvature < 5
  n = 111183 

  Weighted least-squares fit:  Y = 108.8 + -0.941 X  + 0.00910 X**2 
     at X = 100, Y = 105.7 
     Bad fit. P2 = 0
slope versus dZ, curvature < 15
  n = 287630 

  Weighted least-squares fit:  Y = 107.1 + -0.886 X  + 0.00868 X**2 

curvature versus dZ, slope < 10
  n = 10534 
  X=0, Y = 99.47 +/- 46.65 
  Weighted least-squares fit:  Y = 97.9 + 1.451 X  + 0.00580 X**2 


Number of samples 532116
Max dz = 900
Mean dz = 81
RMS dz = 103.923048454
100cm = 63.8785527968 percentile value of dz