curvature versus slope
  n = 892990 
  X=0, Y = 4.91 +/- 3.16 
  Weighted least-squares fit:  Y = 2.9 + 5.509 X  + -0.10062 X**2 

slope versus dZ, curvature < 5
  n = 661223 
  X=0, Y = 7.68 +/- 4.70 
  Weighted least-squares fit:  Y = 6.4 + 0.491 X  + -0.00140 X**2 
     at X = 100, Y = 41.6 
     effective RMSE xy = 64.5 

slope versus dZ, curvature < 15
  n = 842751 
  X=0, Y = 7.73 +/- 4.74 
  Weighted least-squares fit:  Y = 6.8 + 0.506 X  + -0.00047 X**2 

curvature versus dZ, slope < 10
  n = 799428 
  X=0, Y = 7.81 +/- 4.59 
  Weighted least-squares fit:  Y = 7.4 + 1.360 X  + 0.08350 X**2 


Number of samples 893965
Max dz = 400
Mean dz = 8
RMS dz = 13.7113092008
100cm = 99.8704647274 percentile value of dz