curvature versus slope
  n = 1320078 
  X=0, Y = 12.28 +/- 9.55 
  Weighted least-squares fit:  Y = 13.2 + 4.711 X  + -0.05350 X**2 

slope versus dZ, curvature < 5
  n = 622468 
  X=0, Y = 9.64 +/- 7.16 
  Weighted least-squares fit:  Y = 14.8 + 0.211 X  + 0.00083 X**2 
     at X = 100, Y = 44.1 
     effective RMSE xy = 65.2 

slope versus dZ, curvature < 15
  n = 1050384 
  X=0, Y = 9.59 +/- 6.51 
  Weighted least-squares fit:  Y = 14.9 + 0.302 X  + 0.00074 X**2 

curvature versus dZ, slope < 10
  n = 733989 
  X=0, Y = 14.16 +/- 9.74 
  Weighted least-squares fit:  Y = 15.0 + 1.196 X  + 0.06638 X**2 


Number of samples 1341045
Max dz = 900
Mean dz = 21
RMS dz = 40.8166632639
100cm = 97.6358735165 percentile value of dz