curvature versus slope
  n = 277410 
  X=0, Y = 19.53 +/- 14.35 
  Weighted least-squares fit:  Y = 27.6 + 3.554 X  + -0.03966 X**2 

slope versus dZ, curvature < 5
  n = 89396 
  X=0, Y = 16.22 +/- 7.70 
  Weighted least-squares fit:  Y = 12.6 + 0.416 X  + 0.00171 X**2 
     at X = 100, Y = 71.3 
     effective RMSE xy = 110.3 

slope versus dZ, curvature < 15
  n = 165968 
  X=0, Y = 14.60 +/- 7.26 
  Weighted least-squares fit:  Y = 12.5 + 0.423 X  + 0.00188 X**2 

curvature versus dZ, slope < 10
  n = 59696 
  X=0, Y = 15.67 +/- 8.82 
  Weighted least-squares fit:  Y = 14.8 + 0.626 X  + 0.13371 X**2 


Number of samples 280810
Max dz = 900
Mean dz = 32
RMS dz = 66.0908465674
100cm = 94.5553933264 percentile value of dz