curvature versus slope
  n = 298108 
  X=0, Y = 10.82 +/- 8.39 
  Weighted least-squares fit:  Y = 10.5 + 4.762 X  + -0.05229 X**2 

slope versus dZ, curvature < 5
  n = 199074 
  X=0, Y = 13.14 +/- 7.84 
  Weighted least-squares fit:  Y = 10.5 + 0.829 X  + -0.00550 X**2 
     at X = 100, Y = 38.4 
     effective RMSE xy = 58.0 

slope versus dZ, curvature < 15
  n = 266861 
  X=0, Y = 12.90 +/- 7.77 
  Weighted least-squares fit:  Y = 10.7 + 0.711 X  + -0.00293 X**2 

curvature versus dZ, slope < 10
  n = 207640 
  X=0, Y = 14.17 +/- 8.76 
  Weighted least-squares fit:  Y = 13.0 + 0.365 X  + 0.13590 X**2 


Number of samples 300956
Max dz = 900
Mean dz = 16
RMS dz = 29.883105595
100cm = 98.9569903906 percentile value of dz