curvature versus slope
  n = 693672 
  X=0, Y = 7.98 +/- 6.68 
  Weighted least-squares fit:  Y = 9.2 + 4.489 X  + -0.04878 X**2 

slope versus dZ, curvature < 5
  n = 372605 
  X=0, Y = 7.79 +/- 5.85 
  Weighted least-squares fit:  Y = 8.6 + 0.364 X  + 0.00104 X**2 
     at X = 100, Y = 55.4 
     effective RMSE xy = 85.9 

slope versus dZ, curvature < 15
  n = 558493 
  X=0, Y = 7.98 +/- 5.92 
  Weighted least-squares fit:  Y = 9.2 + 0.440 X  + 0.00012 X**2 

curvature versus dZ, slope < 10
  n = 429547 
  X=0, Y = 9.16 +/- 6.18 
  Weighted least-squares fit:  Y = 9.0 + 2.343 X  + 0.03030 X**2 


Number of samples 700048
Max dz = 900
Mean dz = 14
RMS dz = 34.3074335968
100cm = 99.0106392705 percentile value of dz