curvature versus slope
  n = 259148 
  X=0, Y = 12.33 +/- 9.87 
  Weighted least-squares fit:  Y = 21.1 + 4.005 X  + -0.04529 X**2 

slope versus dZ, curvature < 5
  n = 135569 
  X=0, Y = 9.79 +/- 4.78 
  Weighted least-squares fit:  Y = 6.6 + 0.157 X  + 0.00054 X**2 
     at X = 100, Y = 27.8 
     effective RMSE xy = 42.4 

slope versus dZ, curvature < 15
  n = 180527 
  X=0, Y = 9.58 +/- 4.78 
  Weighted least-squares fit:  Y = 6.6 + 0.223 X  + 0.00045 X**2 

curvature versus dZ, slope < 10
  n = 123043 
  X=0, Y = 7.35 +/- 4.34 
  Weighted least-squares fit:  Y = 7.0 + 0.978 X  + 0.09194 X**2 


Number of samples 262184
Max dz = 900
Mean dz = 16
RMS dz = 43.0581002832
100cm = 98.0197113478 percentile value of dz