curvature versus slope
  n = 592916 
  X=0, Y = 7.56 +/- 6.29 
  Weighted least-squares fit:  Y = 9.9 + 4.732 X  + -0.05381 X**2 

slope versus dZ, curvature < 5
  n = 390408 
  X=0, Y = 7.97 +/- 4.94 
  Weighted least-squares fit:  Y = 6.5 + 0.280 X  + -0.00019 X**2 
     at X = 100, Y = 32.6 
     effective RMSE xy = 50.2 

slope versus dZ, curvature < 15
  n = 501303 
  X=0, Y = 8.24 +/- 5.07 
  Weighted least-squares fit:  Y = 6.7 + 0.312 X  + 0.00019 X**2 

curvature versus dZ, slope < 10
  n = 440347 
  X=0, Y = 7.26 +/- 4.71 
  Weighted least-squares fit:  Y = 6.3 + 1.907 X  + 0.01187 X**2 


Number of samples 598382
Max dz = 900
Mean dz = 11
RMS dz = 24.7386337537
100cm = 98.9802500744 percentile value of dz