curvature versus slope
  n = 802147 
  X=0, Y = 4.83 +/- 3.53 
  Weighted least-squares fit:  Y = 2.3 + 5.600 X  + -0.06937 X**2 

slope versus dZ, curvature < 5
  n = 638565 
  X=0, Y = 9.81 +/- 6.42 
  Weighted least-squares fit:  Y = 13.1 + 0.895 X  + -0.00697 X**2 
     at X = 100, Y = 32.8 
     effective RMSE xy = 47.3 

slope versus dZ, curvature < 15
  n = 777925 
  X=0, Y = 10.23 +/- 6.85 
  Weighted least-squares fit:  Y = 14.4 + 0.725 X  + -0.00412 X**2 

curvature versus dZ, slope < 10
  n = 749055 
  X=0, Y = 15.56 +/- 11.22 
  Weighted least-squares fit:  Y = 14.5 + 3.227 X  + -0.13722 X**2 


Number of samples 804067
Max dz = 900
Mean dz = 13
RMS dz = 23.0651251893
100cm = 99.7377084248 percentile value of dz