curvature versus slope
  n = 110552 
  X=0, Y = 5.15 +/- 3.34 
  Weighted least-squares fit:  Y = 8.5 + 4.821 X  + -0.05500 X**2 

slope versus dZ, curvature < 5
  n = 84881 
  X=0, Y = 15.54 +/- 9.45 
  Weighted least-squares fit:  Y = 12.2 + 0.709 X  + -0.00232 X**2 
     at X = 100, Y = 59.9 
     effective RMSE xy = 92.1 

slope versus dZ, curvature < 15
  n = 92625 
  X=0, Y = 15.54 +/- 9.45 
  Weighted least-squares fit:  Y = 12.7 + 0.616 X  + 0.00101 X**2 

curvature versus dZ, slope < 10
  n = 86842 
  X=0, Y = 14.51 +/- 7.70 
  Weighted least-squares fit:  Y = 14.2 + 1.861 X  + -0.10418 X**2 


Number of samples 112421
Max dz = 900
Mean dz = 30
RMS dz = 85.6270985144
100cm = 93.3322066162 percentile value of dz