curvature versus slope
  n = 548259 
  X=0, Y = 8.45 +/- 7.61 
  Weighted least-squares fit:  Y = 9.6 + 5.299 X  + -0.06520 X**2 

slope versus dZ, curvature < 5
  n = 336853 
  X=0, Y = 20.89 +/- 12.25 
  Weighted least-squares fit:  Y = 14.9 + 0.026 X  + 0.00343 X**2 
     at X = 100, Y = 51.9 
     effective RMSE xy = 78.0 

slope versus dZ, curvature < 15
  n = 473869 
  X=0, Y = 20.06 +/- 11.98 
  Weighted least-squares fit:  Y = 14.1 + 0.161 X  + 0.00221 X**2 

curvature versus dZ, slope < 10
  n = 417584 
  X=0, Y = 16.98 +/- 11.02 
  Weighted least-squares fit:  Y = 17.0 + -0.906 X  + 0.21229 X**2 


Number of samples 553484
Max dz = 900
Mean dz = 16
RMS dz = 27.0924343683
100cm = 98.9363739512 percentile value of dz