curvature versus slope
  n = 484268 
  X=0, Y = 9.13 +/- 7.59 
  Weighted least-squares fit:  Y = 23.6 + 4.052 X  + -0.04684 X**2 

slope versus dZ, curvature < 5
  n = 198226 
  X=0, Y = 8.66 +/- 4.59 
  Weighted least-squares fit:  Y = 5.1 + 0.677 X  + -0.00016 X**2 
     at X = 100, Y = 71.2 
     effective RMSE xy = 111.6 

slope versus dZ, curvature < 15
  n = 258521 
  X=0, Y = 8.91 +/- 4.80 
  Weighted least-squares fit:  Y = 5.1 + 0.770 X  + -0.00105 X**2 

curvature versus dZ, slope < 10
  n = 192890 
  X=0, Y = 7.71 +/- 4.88 
  Weighted least-squares fit:  Y = 6.5 + 3.559 X  + -0.09777 X**2 


Number of samples 489004
Max dz = 900
Mean dz = 38
RMS dz = 78.2112523874
100cm = 89.117675929 percentile value of dz