curvature versus slope
  n = 344330 
  X=0, Y = 8.83 +/- 6.92 
  Weighted least-squares fit:  Y = 9.4 + 4.462 X  + -0.04779 X**2 

slope versus dZ, curvature < 5
  n = 189208 
  X=0, Y = 13.84 +/- 6.66 
  Weighted least-squares fit:  Y = 9.9 + 0.184 X  + 0.00003 X**2 
     at X = 100, Y = 28.5 
     effective RMSE xy = 42.1 

slope versus dZ, curvature < 15
  n = 292566 
  X=0, Y = 14.22 +/- 6.85 
  Weighted least-squares fit:  Y = 10.4 + 0.184 X  + 0.00067 X**2 

curvature versus dZ, slope < 10
  n = 232077 
  X=0, Y = 10.91 +/- 5.97 
  Weighted least-squares fit:  Y = 10.2 + 0.816 X  + 0.07216 X**2 


Number of samples 346724
Max dz = 900
Mean dz = 13
RMS dz = 29.5803989155
100cm = 99.2460862242 percentile value of dz