curvature versus slope
  n = 608351 
  X=0, Y = 7.74 +/- 6.28 
  Weighted least-squares fit:  Y = 10.3 + 4.713 X  + -0.05324 X**2 

slope versus dZ, curvature < 5
  n = 389255 
  X=0, Y = 9.74 +/- 6.82 
  Weighted least-squares fit:  Y = 9.5 + 0.301 X  + 0.00117 X**2 
     at X = 100, Y = 51.3 
     effective RMSE xy = 79.2 

slope versus dZ, curvature < 15
  n = 515115 
  X=0, Y = 9.81 +/- 6.75 
  Weighted least-squares fit:  Y = 9.5 + 0.350 X  + 0.00069 X**2 

curvature versus dZ, slope < 10
  n = 430838 
  X=0, Y = 10.71 +/- 7.30 
  Weighted least-squares fit:  Y = 10.0 + 1.276 X  + 0.06514 X**2 


Number of samples 616340
Max dz = 900
Mean dz = 14
RMS dz = 32.7871926215
100cm = 98.5443099588 percentile value of dz