curvature versus slope
  n = 223707 
  X=0, Y = 9.67 +/- 8.50 
  Weighted least-squares fit:  Y = 16.1 + 4.238 X  + -0.04780 X**2 

slope versus dZ, curvature < 5
  n = 100796 
  X=0, Y = 9.90 +/- 6.22 
  Weighted least-squares fit:  Y = 10.5 + 0.199 X  + 0.00156 X**2 
     at X = 100, Y = 46.0 
     effective RMSE xy = 70.3 

slope versus dZ, curvature < 15
  n = 149860 
  X=0, Y = 10.55 +/- 6.46 
  Weighted least-squares fit:  Y = 10.2 + 0.325 X  + 0.00093 X**2 

curvature versus dZ, slope < 10
  n = 126591 
  X=0, Y = 11.01 +/- 6.04 
  Weighted least-squares fit:  Y = 10.3 + 1.278 X  + 0.06501 X**2 


Number of samples 228158
Max dz = 900
Mean dz = 24
RMS dz = 46.465040622
100cm = 95.7301519123 percentile value of dz