curvature versus slope
  n = 352536 
  X=0, Y = 17.28 +/- 13.38 
  Weighted least-squares fit:  Y = 24.3 + 3.401 X  + -0.03470 X**2 

slope versus dZ, curvature < 5
  n = 76872 
  X=0, Y = 14.56 +/- 5.06 
  Weighted least-squares fit:  Y = 13.3 + 0.242 X  + 0.00289 X**2 
     at X = 100, Y = 66.4 
     effective RMSE xy = 102.3 

slope versus dZ, curvature < 15
  n = 170804 
  X=0, Y = 14.04 +/- 5.13 
  Weighted least-squares fit:  Y = 13.1 + 0.323 X  + 0.00220 X**2 

curvature versus dZ, slope < 10
  n = 68905 
  X=0, Y = 15.10 +/- 6.04 
  Weighted least-squares fit:  Y = 13.8 + 1.327 X  + 0.06551 X**2 


Number of samples 357661
Max dz = 900
Mean dz = 32
RMS dz = 62.5299928035
100cm = 94.2451091956 percentile value of dz