curvature versus slope
  n = 465440 
  X=0, Y = 8.59 +/- 6.92 
  Weighted least-squares fit:  Y = 13.4 + 4.584 X  + -0.05184 X**2 

slope versus dZ, curvature < 5
  n = 275624 
  X=0, Y = 12.90 +/- 6.59 
  Weighted least-squares fit:  Y = 11.4 + 0.197 X  + 0.00229 X**2 
     at X = 100, Y = 53.9 
     effective RMSE xy = 82.8 

slope versus dZ, curvature < 15
  n = 374088 
  X=0, Y = 13.21 +/- 6.74 
  Weighted least-squares fit:  Y = 11.3 + 0.244 X  + 0.00190 X**2 

curvature versus dZ, slope < 10
  n = 297718 
  X=0, Y = 12.83 +/- 7.65 
  Weighted least-squares fit:  Y = 12.0 + 0.815 X  + 0.05271 X**2 


Number of samples 472408
Max dz = 900
Mean dz = 19
RMS dz = 45.3541618818
100cm = 97.4824727778 percentile value of dz