curvature versus slope
  n = 241504 
  X=0, Y = 47.93 +/- 28.18 
  Weighted least-squares fit:  Y = 66.8 + 1.389 X  + -0.01462 X**2 

slope versus dZ, curvature < 5
  n = 25647 

  Weighted least-squares fit:  Y = 8.4 + 0.703 X  + 0.00214 X**2 
     at X = 100, Y = 100.0 
     effective RMSE xy = 156.5 

slope versus dZ, curvature < 15
  n = 68164 

  Weighted least-squares fit:  Y = 7.7 + 0.854 X  + 0.00078 X**2 

curvature versus dZ, slope < 10
  n = 2989 
  X=0, Y = 15.00 +/- 10.25 
  Weighted least-squares fit:  Y = 14.9 + 0.466 X  + 0.12818 X**2 


Number of samples 244267
Max dz = 900
Mean dz = 73
RMS dz = 109.004587059
100cm = 74.2986158589 percentile value of dz