curvature versus slope
  n = 371536 
  X=0, Y = 14.43 +/- 10.37 
  Weighted least-squares fit:  Y = 17.4 + 3.970 X  + -0.04194 X**2 

slope versus dZ, curvature < 5
  n = 89003 

  Weighted least-squares fit:  Y = 90.7 + -0.192 X  + 0.00170 X**2 
     at X = 100, Y = 88.4 
     Bad fit. P2 = 0
slope versus dZ, curvature < 15
  n = 213535 

  Weighted least-squares fit:  Y = 90.4 + -0.162 X  + 0.00229 X**2 

curvature versus dZ, slope < 10
  n = 100750 
  X=0, Y = 88.22 +/- 37.69 
  Weighted least-squares fit:  Y = 91.8 + -1.569 X  + 0.12285 X**2 


Number of samples 373118
Max dz = 900
Mean dz = 85
RMS dz = 108.092552935
100cm = 68.4156218676 percentile value of dz