curvature versus slope
  n = 651213 
  X=0, Y = 69.49 +/- 19.63 
  Weighted least-squares fit:  Y = 74.6 + 0.842 X  + -0.00741 X**2 

slope versus dZ, curvature < 5
  n = 103973 

  Weighted least-squares fit:  Y = 7.1 + 0.124 X  + 0.00088 X**2 
     at X = 100, Y = 28.2 
     effective RMSE xy = 42.9 

slope versus dZ, curvature < 15
  n = 319248 

  Weighted least-squares fit:  Y = 8.9 + 0.107 X  + 0.00092 X**2 

curvature versus dZ, slope < 10
  n = 424 
  X=0, Y = 7.32 +/- 5.19 
  Weighted least-squares fit:  Y = 6.1 + 2.156 X  + -0.06131 X**2 


Number of samples 657009
Max dz = 600
Mean dz = 21
RMS dz = 30.4795013083
100cm = 98.9893593543 percentile value of dz