curvature versus slope
  n = 499392 
  X=0, Y = 10.90 +/- 9.14 
  Weighted least-squares fit:  Y = 16.9 + 4.196 X  + -0.04770 X**2 

slope versus dZ, curvature < 5
  n = 293176 
  X=0, Y = 7.33 +/- 4.55 
  Weighted least-squares fit:  Y = 6.1 + 0.340 X  + -0.00009 X**2 
     at X = 100, Y = 39.1 
     effective RMSE xy = 60.7 

slope versus dZ, curvature < 15
  n = 373653 
  X=0, Y = 7.49 +/- 4.63 
  Weighted least-squares fit:  Y = 6.1 + 0.366 X  + 0.00019 X**2 

curvature versus dZ, slope < 10
  n = 286245 
  X=0, Y = 7.51 +/- 4.54 
  Weighted least-squares fit:  Y = 6.7 + 1.462 X  + 0.00646 X**2 


Number of samples 507236
Max dz = 900
Mean dz = 16
RMS dz = 42.3792402008
100cm = 97.4769140992 percentile value of dz