curvature versus slope
  n = 2843515 
  X=0, Y = 5.50 +/- 3.73 
  Weighted least-squares fit:  Y = 2.7 + 5.297 X  + -0.06343 X**2 

slope versus dZ, curvature < 5
  n = 2016722 
  X=0, Y = 7.53 +/- 4.51 
  Weighted least-squares fit:  Y = 9.1 + 0.315 X  + -0.00175 X**2 
     at X = 100, Y = 23.1 
     effective RMSE xy = 33.4 

slope versus dZ, curvature < 15
  n = 2728319 
  X=0, Y = 7.82 +/- 4.76 
  Weighted least-squares fit:  Y = 10.0 + 0.240 X  + 0.00031 X**2 

curvature versus dZ, slope < 10
  n = 2449852 
  X=0, Y = 9.36 +/- 6.14 
  Weighted least-squares fit:  Y = 8.9 + 2.068 X  + -0.02152 X**2 


Number of samples 2845614
Max dz = 500
Mean dz = 9
RMS dz = 13.3041346957
100cm = 99.9163625144 percentile value of dz