curvature versus slope
  n = 702073 
  X=0, Y = 7.90 +/- 6.58 
  Weighted least-squares fit:  Y = 17.4 + 4.467 X  + -0.05291 X**2 

slope versus dZ, curvature < 5
  n = 387212 
  X=0, Y = 30.45 +/- 13.28 
  Weighted least-squares fit:  Y = 22.7 + -0.199 X  + 0.00582 X**2 
     at X = 100, Y = 61.0 
     effective RMSE xy = 89.0 

slope versus dZ, curvature < 15
  n = 472681 
  X=0, Y = 30.33 +/- 13.28 
  Weighted least-squares fit:  Y = 21.4 + 0.007 X  + 0.00397 X**2 

curvature versus dZ, slope < 10
  n = 382749 
  X=0, Y = 25.62 +/- 14.85 
  Weighted least-squares fit:  Y = 24.0 + -0.920 X  + 0.19522 X**2 


Number of samples 716363
Max dz = 900
Mean dz = 33
RMS dz = 53.9629502529
100cm = 93.5235348559 percentile value of dz