curvature versus slope
  n = 1035531 
  X=0, Y = 68.52 +/- 22.54 
  Weighted least-squares fit:  Y = 83.3 + 0.564 X  + -0.00462 X**2 

slope versus dZ, curvature < 5
  n = 23209 

  Weighted least-squares fit:  Y = 7.6 + -0.054 X  + 0.00252 X**2 
     at X = 100, Y = 27.4 
     effective RMSE xy = 41.3 

slope versus dZ, curvature < 15
  n = 148988 

  Weighted least-squares fit:  Y = 6.8 + 0.126 X  + 0.00091 X**2 

curvature versus dZ, slope < 10
  n = 194 
  X=0, Y = 8.94 +/- 5.81 
  Weighted least-squares fit:  Y = 8.7 + -0.790 X  + 0.13155 X**2 


Number of samples 1054055
Max dz = 900
Mean dz = 32
RMS dz = 48.8159809898
100cm = 95.111450541 percentile value of dz