curvature versus slope
  n = 385820 
  X=0, Y = 10.94 +/- 8.02 
  Weighted least-squares fit:  Y = 14.9 + 4.447 X  + -0.05074 X**2 

slope versus dZ, curvature < 5
  n = 239518 
  X=0, Y = 13.11 +/- 7.69 
  Weighted least-squares fit:  Y = 11.7 + 0.183 X  + 0.00088 X**2 
     at X = 100, Y = 38.7 
     effective RMSE xy = 58.0 

slope versus dZ, curvature < 15
  n = 309322 
  X=0, Y = 13.05 +/- 7.59 
  Weighted least-squares fit:  Y = 11.5 + 0.234 X  + 0.00086 X**2 

curvature versus dZ, slope < 10
  n = 221049 
  X=0, Y = 12.81 +/- 7.82 
  Weighted least-squares fit:  Y = 12.7 + 0.505 X  + 0.09000 X**2 


Number of samples 390020
Max dz = 900
Mean dz = 17
RMS dz = 41.8330013267
100cm = 98.276242244 percentile value of dz