curvature versus slope
  n = 429871 
  X=0, Y = 10.16 +/- 7.34 
  Weighted least-squares fit:  Y = 16.8 + 4.312 X  + -0.04887 X**2 

slope versus dZ, curvature < 5
  n = 190830 
  X=0, Y = 8.33 +/- 4.91 
  Weighted least-squares fit:  Y = 9.8 + 0.516 X  + -0.00016 X**2 
     at X = 100, Y = 59.8 
     effective RMSE xy = 92.7 

slope versus dZ, curvature < 15
  n = 294132 
  X=0, Y = 8.46 +/- 4.77 
  Weighted least-squares fit:  Y = 10.3 + 0.510 X  + 0.00008 X**2 

curvature versus dZ, slope < 10
  n = 208623 
  X=0, Y = 11.60 +/- 8.09 
  Weighted least-squares fit:  Y = 11.4 + 1.209 X  + 0.13409 X**2 


Number of samples 436352
Max dz = 900
Mean dz = 26
RMS dz = 57.3149195236
100cm = 94.8360497947 percentile value of dz