curvature versus slope
  n = 561425 
  X=0, Y = 10.49 +/- 9.19 
  Weighted least-squares fit:  Y = 13.0 + 4.241 X  + -0.04653 X**2 

slope versus dZ, curvature < 5
  n = 307885 
  X=0, Y = 6.75 +/- 6.92 
  Weighted least-squares fit:  Y = 10.4 + 0.205 X  + 0.00314 X**2 
     at X = 100, Y = 62.3 
     effective RMSE xy = 96.4 

slope versus dZ, curvature < 15
  n = 465468 
  X=0, Y = 7.30 +/- 7.35 
  Weighted least-squares fit:  Y = 10.9 + 0.225 X  + 0.00354 X**2 

curvature versus dZ, slope < 10
  n = 344988 
  X=0, Y = 10.58 +/- 8.40 
  Weighted least-squares fit:  Y = 10.5 + 1.709 X  + 0.06927 X**2 


Number of samples 563596
Max dz = 900
Mean dz = 16
RMS dz = 58.8472599192
100cm = 98.5510897877 percentile value of dz