curvature versus slope
  n = 668653 
  X=0, Y = 8.00 +/- 6.73 
  Weighted least-squares fit:  Y = 9.6 + 4.657 X  + -0.05625 X**2 

slope versus dZ, curvature < 5
  n = 359497 
  X=0, Y = 11.24 +/- 7.50 
  Weighted least-squares fit:  Y = 9.9 + 0.391 X  + 0.00160 X**2 
     at X = 100, Y = 65.0 
     effective RMSE xy = 101.0 

slope versus dZ, curvature < 15
  n = 537154 
  X=0, Y = 11.60 +/- 7.73 
  Weighted least-squares fit:  Y = 10.1 + 0.435 X  + 0.00098 X**2 

curvature versus dZ, slope < 10
  n = 452103 
  X=0, Y = 11.71 +/- 6.65 
  Weighted least-squares fit:  Y = 10.6 + 1.654 X  + 0.05524 X**2 


Number of samples 684127
Max dz = 900
Mean dz = 18
RMS dz = 34.4963766213
100cm = 97.5073341646 percentile value of dz