curvature versus slope
  n = 500878 
  X=0, Y = 9.89 +/- 8.97 
  Weighted least-squares fit:  Y = 16.4 + 4.191 X  + -0.04735 X**2 

slope versus dZ, curvature < 5
  n = 231061 
  X=0, Y = 10.72 +/- 7.02 
  Weighted least-squares fit:  Y = 7.7 + 0.236 X  + 0.00195 X**2 
     at X = 100, Y = 50.7 
     effective RMSE xy = 78.8 

slope versus dZ, curvature < 15
  n = 334568 
  X=0, Y = 10.94 +/- 7.11 
  Weighted least-squares fit:  Y = 7.9 + 0.317 X  + 0.00138 X**2 

curvature versus dZ, slope < 10
  n = 241320 
  X=0, Y = 8.67 +/- 5.90 
  Weighted least-squares fit:  Y = 7.7 + 1.925 X  + 0.02993 X**2 


Number of samples 509560
Max dz = 900
Mean dz = 21
RMS dz = 46.7118828565
100cm = 96.4522332993 percentile value of dz