curvature versus slope
  n = 403590 
  X=0, Y = 12.41 +/- 10.33 
  Weighted least-squares fit:  Y = 15.1 + 3.793 X  + -0.04069 X**2 

slope versus dZ, curvature < 5
  n = 172050 
  X=0, Y = 11.34 +/- 8.07 
  Weighted least-squares fit:  Y = 13.4 + 0.011 X  + 0.00487 X**2 
     at X = 100, Y = 63.2 
     effective RMSE xy = 97.1 

slope versus dZ, curvature < 15
  n = 294910 
  X=0, Y = 13.03 +/- 8.85 
  Weighted least-squares fit:  Y = 13.3 + 0.110 X  + 0.00449 X**2 

curvature versus dZ, slope < 10
  n = 199586 
  X=0, Y = 13.76 +/- 7.98 
  Weighted least-squares fit:  Y = 12.2 + 1.737 X  + 0.05831 X**2 


Number of samples 410252
Max dz = 900
Mean dz = 22
RMS dz = 50.6853035899
100cm = 96.4470618059 percentile value of dz