curvature versus slope
  n = 278087 
  X=0, Y = 12.79 +/- 11.44 
  Weighted least-squares fit:  Y = 24.4 + 3.063 X  + -0.03196 X**2 

slope versus dZ, curvature < 5
  n = 98317 
  X=0, Y = 7.41 +/- 4.99 
  Weighted least-squares fit:  Y = 7.6 + 0.272 X  + 0.00114 X**2 
     at X = 100, Y = 46.3 
     effective RMSE xy = 71.7 

slope versus dZ, curvature < 15
  n = 140959 
  X=0, Y = 7.33 +/- 4.84 
  Weighted least-squares fit:  Y = 7.7 + 0.299 X  + 0.00136 X**2 

curvature versus dZ, slope < 10
  n = 100667 
  X=0, Y = 8.98 +/- 6.11 
  Weighted least-squares fit:  Y = 7.7 + 1.729 X  + 0.03540 X**2 


Number of samples 281780
Max dz = 900
Mean dz = 25
RMS dz = 51.5169874896
100cm = 95.3076868479 percentile value of dz