curvature versus slope
  n = 441940 
  X=0, Y = 7.68 +/- 5.94 
  Weighted least-squares fit:  Y = 11.3 + 4.466 X  + -0.05046 X**2 

slope versus dZ, curvature < 5
  n = 275154 
  X=0, Y = 5.68 +/- 3.37 
  Weighted least-squares fit:  Y = 4.9 + 0.289 X  + 0.00148 X**2 
     at X = 100, Y = 48.6 
     effective RMSE xy = 76.0 

slope versus dZ, curvature < 15
  n = 347049 
  X=0, Y = 6.10 +/- 3.62 
  Weighted least-squares fit:  Y = 4.8 + 0.372 X  + 0.00088 X**2 

curvature versus dZ, slope < 10
  n = 301648 
  X=0, Y = 5.79 +/- 3.69 
  Weighted least-squares fit:  Y = 5.1 + 1.477 X  + 0.05486 X**2 


Number of samples 445303
Max dz = 900
Mean dz = 16
RMS dz = 59.2452529744
100cm = 97.1677711581 percentile value of dz