curvature versus slope
  n = 797067 
  X=0, Y = 11.72 +/- 10.08 
  Weighted least-squares fit:  Y = 14.7 + 4.896 X  + -0.06040 X**2 

slope versus dZ, curvature < 5
  n = 403009 
  X=0, Y = 7.48 +/- 4.83 
  Weighted least-squares fit:  Y = 7.1 + 0.316 X  + 0.00177 X**2 
     at X = 100, Y = 56.4 
     effective RMSE xy = 88.0 

slope versus dZ, curvature < 15
  n = 609625 
  X=0, Y = 7.80 +/- 5.13 
  Weighted least-squares fit:  Y = 7.5 + 0.385 X  + 0.00102 X**2 

curvature versus dZ, slope < 10
  n = 426536 
  X=0, Y = 8.14 +/- 5.08 
  Weighted least-squares fit:  Y = 7.5 + 1.866 X  + 0.07085 X**2 


Number of samples 813103
Max dz = 900
Mean dz = 16
RMS dz = 33.2415402772
100cm = 97.8370513945 percentile value of dz