curvature versus slope
  n = 1771399 
  X=0, Y = 4.38 +/- 3.16 
  Weighted least-squares fit:  Y = 3.6 + 3.542 X  + -0.03417 X**2 

slope versus dZ, curvature < 5
  n = 1143463 
  X=0, Y = 1.96 +/- 2.40 
  Weighted least-squares fit:  Y = 4.4 + 0.734 X  + -0.00587 X**2 
     at X = 100, Y = 19.2 
     effective RMSE xy = 29.3 

slope versus dZ, curvature < 15
  n = 1587998 
  X=0, Y = 2.14 +/- 2.60 
  Weighted least-squares fit:  Y = 5.4 + 0.740 X  + -0.00525 X**2 

curvature versus dZ, slope < 10
  n = 1470278 
  X=0, Y = 5.76 +/- 5.13 
  Weighted least-squares fit:  Y = 5.7 + 3.309 X  + -0.13285 X**2 


Number of samples 1771882
Max dz = 300
Mean dz = 8
RMS dz = 12.124355653
100cm = 99.9655168911 percentile value of dz