curvature versus slope
  n = 529183 
  X=0, Y = 21.02 +/- 14.38 
  Weighted least-squares fit:  Y = 41.1 + 3.024 X  + -0.03247 X**2 

slope versus dZ, curvature < 5
  n = 100219 
  X=0, Y = 5.85 +/- 3.07 
  Weighted least-squares fit:  Y = 13.2 + 0.003 X  + 0.00248 X**2 
     at X = 100, Y = 38.4 
     effective RMSE xy = 56.6 

slope versus dZ, curvature < 15
  n = 190036 
  X=0, Y = 5.85 +/- 3.07 
  Weighted least-squares fit:  Y = 13.0 + 0.092 X  + 0.00246 X**2 

curvature versus dZ, slope < 10
  n = 53444 
  X=0, Y = 12.38 +/- 8.95 
  Weighted least-squares fit:  Y = 12.7 + 2.190 X  + -0.14433 X**2 


Number of samples 536874
Max dz = 900
Mean dz = 38
RMS dz = 63.9140047251
100cm = 90.7030327414 percentile value of dz