curvature versus slope
  n = 1457212 
  X=0, Y = 8.16 +/- 6.45 
  Weighted least-squares fit:  Y = 12.7 + 3.095 X  + -0.03365 X**2 

slope versus dZ, curvature < 5
  n = 639288 
  X=0, Y = 8.50 +/- 5.50 
  Weighted least-squares fit:  Y = 7.4 + 0.221 X  + 0.00173 X**2 
     at X = 100, Y = 46.8 
     effective RMSE xy = 72.6 

slope versus dZ, curvature < 15
  n = 974397 
  X=0, Y = 8.44 +/- 5.37 
  Weighted least-squares fit:  Y = 7.2 + 0.310 X  + 0.00070 X**2 

curvature versus dZ, slope < 10
  n = 805082 
  X=0, Y = 8.23 +/- 5.31 
  Weighted least-squares fit:  Y = 6.8 + 1.633 X  + 0.01499 X**2 


Number of samples 1473631
Max dz = 900
Mean dz = 14
RMS dz = 27.748873851
100cm = 98.6521049028 percentile value of dz