curvature versus slope
  n = 325617 
  X=0, Y = 37.84 +/- 25.41 
  Weighted least-squares fit:  Y = 51.4 + 2.016 X  + -0.02023 X**2 

slope versus dZ, curvature < 5
  n = 40040 

  Weighted least-squares fit:  Y = 135.3 + -1.020 X  + 0.00549 X**2 
     at X = 100, Y = 88.1 
     Bad fit. P2 = 0
slope versus dZ, curvature < 15
  n = 111604 

  Weighted least-squares fit:  Y = 134.4 + -0.993 X  + 0.00575 X**2 

curvature versus dZ, slope < 10
  n = 10297 
  X=0, Y = 131.75 +/- 15.88 
  Weighted least-squares fit:  Y = 129.9 + -2.141 X  + 0.17857 X**2 


Number of samples 327375
Max dz = 900
Mean dz = 112
RMS dz = 144.3537322
100cm = 45.1604429171 percentile value of dz