curvature versus slope
  n = 372858 
  X=0, Y = 11.03 +/- 9.76 
  Weighted least-squares fit:  Y = 18.4 + 4.201 X  + -0.04774 X**2 

slope versus dZ, curvature < 5
  n = 202346 
  X=0, Y = 7.27 +/- 5.03 
  Weighted least-squares fit:  Y = 6.5 + 0.471 X  + -0.00093 X**2 
     at X = 100, Y = 44.3 
     effective RMSE xy = 68.8 

slope versus dZ, curvature < 15
  n = 269941 
  X=0, Y = 7.66 +/- 5.19 
  Weighted least-squares fit:  Y = 6.8 + 0.476 X  + -0.00006 X**2 

curvature versus dZ, slope < 10
  n = 215054 
  X=0, Y = 8.46 +/- 5.53 
  Weighted least-squares fit:  Y = 7.0 + 2.323 X  + 0.00895 X**2 


Number of samples 377529
Max dz = 900
Mean dz = 22
RMS dz = 58.6088730484
100cm = 95.7989982227 percentile value of dz