curvature versus slope
  n = 876027 
  X=0, Y = 8.31 +/- 7.69 
  Weighted least-squares fit:  Y = 9.0 + 4.686 X  + -0.05341 X**2 

slope versus dZ, curvature < 5
  n = 482049 
  X=0, Y = 6.18 +/- 5.80 
  Weighted least-squares fit:  Y = 8.5 + 0.357 X  + 0.00055 X**2 
     at X = 100, Y = 49.7 
     effective RMSE xy = 76.9 

slope versus dZ, curvature < 15
  n = 732380 
  X=0, Y = 6.46 +/- 6.00 
  Weighted least-squares fit:  Y = 9.7 + 0.368 X  + 0.00051 X**2 

curvature versus dZ, slope < 10
  n = 598659 
  X=0, Y = 8.28 +/- 6.64 
  Weighted least-squares fit:  Y = 8.9 + 2.528 X  + -0.03555 X**2 


Number of samples 880698
Max dz = 900
Mean dz = 13
RMS dz = 41.4125584817
100cm = 99.2109667559 percentile value of dz