curvature versus slope
  n = 364711 
  X=0, Y = 11.89 +/- 9.77 
  Weighted least-squares fit:  Y = 21.5 + 3.635 X  + -0.03941 X**2 

slope versus dZ, curvature < 5
  n = 126134 
  X=0, Y = 10.59 +/- 7.08 
  Weighted least-squares fit:  Y = 9.0 + 0.266 X  + 0.00144 X**2 
     at X = 100, Y = 50.0 
     effective RMSE xy = 77.3 

slope versus dZ, curvature < 15
  n = 201938 
  X=0, Y = 10.53 +/- 6.83 
  Weighted least-squares fit:  Y = 9.1 + 0.331 X  + 0.00087 X**2 

curvature versus dZ, slope < 10
  n = 132567 
  X=0, Y = 10.40 +/- 6.05 
  Weighted least-squares fit:  Y = 9.4 + 1.615 X  + 0.03670 X**2 


Number of samples 368593
Max dz = 900
Mean dz = 26
RMS dz = 58.2494635168
100cm = 95.5970406383 percentile value of dz