curvature versus slope
  n = 127004 
  X=0, Y = 12.32 +/- 9.91 
  Weighted least-squares fit:  Y = 25.3 + 3.735 X  + -0.04115 X**2 

slope versus dZ, curvature < 5
  n = 52303 
  X=0, Y = 11.07 +/- 8.55 
  Weighted least-squares fit:  Y = 9.1 + 0.243 X  + 0.00241 X**2 
     at X = 100, Y = 57.6 
     effective RMSE xy = 89.3 

slope versus dZ, curvature < 15
  n = 77788 
  X=0, Y = 11.10 +/- 8.25 
  Weighted least-squares fit:  Y = 8.8 + 0.358 X  + 0.00180 X**2 

curvature versus dZ, slope < 10
  n = 49615 
  X=0, Y = 11.35 +/- 8.29 
  Weighted least-squares fit:  Y = 10.6 + 0.400 X  + 0.20334 X**2 


Number of samples 128631
Max dz = 900
Mean dz = 33
RMS dz = 83.0
100cm = 91.9661667872 percentile value of dz