curvature versus slope
  n = 36179 
  X=0, Y = 8.00 +/- 3.36 
  Weighted least-squares fit:  Y = 7.4 + 0.329 X  + 0.00068 X**2 

slope versus dZ, curvature < 5
  n = 8068 

  Weighted least-squares fit:  Y = 27.9 + 1.432 X  + -0.07435 X**2 
     at X = 100, Y = -572.4 
     effective RMSE xy = 898.1 

slope versus dZ, curvature < 15
  n = 18643 

  Weighted least-squares fit:  Y = 32.8 + 0.137 X  + -0.00597 X**2 

curvature versus dZ, slope < 10
  n = 28248 
  X=0, Y = 33.66 +/- 19.32 
  Weighted least-squares fit:  Y = 35.6 + -0.465 X  + 0.00821 X**2 


Number of samples 36242
Max dz = 110
Mean dz = 27
RMS dz = 34.1320963318
100cm = 99.7902985486 percentile value of dz
Mean dz (curv<=5) = 27
RMS dz (curv<=5) = 33.5857112475