curvature versus slope
  n = 838107 
  X=0, Y = 9.63 +/- 8.07 
  Weighted least-squares fit:  Y = 21.5 + 4.083 X  + -0.04659 X**2 

slope versus dZ, curvature < 5
  n = 263398 
  X=0, Y = 5.58 +/- 3.10 
  Weighted least-squares fit:  Y = 6.8 + 0.452 X  + -0.00035 X**2 
     at X = 100, Y = 48.4 
     effective RMSE xy = 75.3 

slope versus dZ, curvature < 15
  n = 408003 
  X=0, Y = 5.73 +/- 3.11 
  Weighted least-squares fit:  Y = 7.3 + 0.506 X  + -0.00040 X**2 

curvature versus dZ, slope < 10
  n = 263613 
  X=0, Y = 7.85 +/- 5.60 
  Weighted least-squares fit:  Y = 7.4 + 2.616 X  + -0.02173 X**2 


Number of samples 854053
Max dz = 900
Mean dz = 31
RMS dz = 54.5068802996
100cm = 93.1706814448 percentile value of dz