curvature versus slope
  n = 514396 
  X=0, Y = 12.14 +/- 7.70 
  Weighted least-squares fit:  Y = 14.5 + 4.475 X  + -0.05064 X**2 

slope versus dZ, curvature < 5
  n = 304895 
  X=0, Y = 5.63 +/- 3.57 
  Weighted least-squares fit:  Y = 7.5 + 0.396 X  + 0.00029 X**2 
     at X = 100, Y = 50.0 
     effective RMSE xy = 77.6 

slope versus dZ, curvature < 15
  n = 426120 
  X=0, Y = 6.34 +/- 3.85 
  Weighted least-squares fit:  Y = 7.6 + 0.416 X  + 0.00023 X**2 

curvature versus dZ, slope < 10
  n = 256907 
  X=0, Y = 9.30 +/- 5.80 
  Weighted least-squares fit:  Y = 9.0 + 1.081 X  + 0.02144 X**2 


Number of samples 521348
Max dz = 900
Mean dz = 17
RMS dz = 41.0243829935
100cm = 97.8841388094 percentile value of dz