curvature versus slope
  n = 582166 
  X=0, Y = 10.48 +/- 7.99 
  Weighted least-squares fit:  Y = 24.5 + 3.996 X  + -0.04563 X**2 

slope versus dZ, curvature < 5
  n = 184020 
  X=0, Y = 89.82 +/- 4.97 
  Weighted least-squares fit:  Y = 84.7 + -0.276 X  + 0.00485 X**2 
     at X = 100, Y = 105.5 
     effective RMSE xy = 98.9 

slope versus dZ, curvature < 15
  n = 278012 
  X=0, Y = 90.74 +/- 5.20 
  Weighted least-squares fit:  Y = 82.7 + -0.183 X  + 0.00409 X**2 

curvature versus dZ, slope < 10
  n = 199527 
  X=0, Y = 85.59 +/- 13.81 
  Weighted least-squares fit:  Y = 84.8 + -3.648 X  + 0.30382 X**2 


Number of samples 585898
Max dz = 900
Mean dz = 88
RMS dz = 110.299592021
100cm = 74.1714428109 percentile value of dz