curvature versus slope
  n = 96241 
  X=0, Y = 18.03 +/- 16.45 
  Weighted least-squares fit:  Y = 49.5 + 2.510 X  + -0.02810 X**2 

slope versus dZ, curvature < 5
  n = 22227 
  X=0, Y = 10.05 +/- 1.42 
  Weighted least-squares fit:  Y = 6.8 + 0.773 X  + 0.00326 X**2 
     at X = 100, Y = 116.7 
     effective RMSE xy = 183.0 

slope versus dZ, curvature < 15
  n = 31816 
  X=0, Y = 10.05 +/- 1.42 
  Weighted least-squares fit:  Y = 6.1 + 1.071 X  + 0.00136 X**2 

curvature versus dZ, slope < 10
  n = 14529 
  X=0, Y = 10.44 +/- 6.10 
  Weighted least-squares fit:  Y = 9.6 + 3.253 X  + 0.02405 X**2 


Number of samples 98824
Max dz = 900
Mean dz = 96
RMS dz = 163.027605024
100cm = 68.2121751801 percentile value of dz
Mean dz (curv<=5) = 18
RMS dz (curv<=5) = 45.0