curvature versus slope
  n = 1654071 
  X=0, Y = 10.35 +/- 9.03 
  Weighted least-squares fit:  Y = 7.2 + 1.536 X  + -0.00814 X**2 

slope versus dZ, curvature < 5
  n = 99619 
  X=0, Y = 2.77 +/- 1.85 
  Weighted least-squares fit:  Y = 2.1 + 0.226 X  + -0.00136 X**2 
     at X = 100, Y = 11.1 
     effective RMSE xy = 17.0 

slope versus dZ, curvature < 15
  n = 368541 
  X=0, Y = 2.74 +/- 1.80 
  Weighted least-squares fit:  Y = 2.6 + 0.152 X  + 0.00050 X**2 

curvature versus dZ, slope < 10
  n = 864839 
  X=0, Y = 2.98 +/- 2.05 
  Weighted least-squares fit:  Y = 2.9 + 0.192 X  + 0.00036 X**2 


Number of samples 1656234
Max dz = 900
Mean dz = 6
RMS dz = 20.7123151772
100cm = 99.8635458516 percentile value of dz
Mean dz (curv<=5) = 2
RMS dz (curv<=5) = 6.92820323028