curvature versus slope
  n = 371693 
  X=0, Y = 10.13 +/- 8.21 
  Weighted least-squares fit:  Y = 14.2 + 3.634 X  + -0.04066 X**2 

slope versus dZ, curvature < 5
  n = 136207 
  X=0, Y = 7.07 +/- 4.42 
  Weighted least-squares fit:  Y = 4.7 + 0.520 X  + 0.00018 X**2 
     at X = 100, Y = 58.4 
     effective RMSE xy = 91.5 

slope versus dZ, curvature < 15
  n = 253172 
  X=0, Y = 6.82 +/- 4.14 
  Weighted least-squares fit:  Y = 5.2 + 0.507 X  + 0.00040 X**2 

curvature versus dZ, slope < 10
  n = 188631 
  X=0, Y = 7.38 +/- 4.67 
  Weighted least-squares fit:  Y = 5.9 + 1.688 X  + 0.03093 X**2 


Number of samples 380895
Max dz = 900
Mean dz = 17
RMS dz = 32.7719392163
100cm = 97.1687735465 percentile value of dz