curvature versus slope
  n = 1924462 
  X=0, Y = 43.38 +/- 26.88 
  Weighted least-squares fit:  Y = 59.6 + 1.906 X  + -0.02031 X**2 

slope versus dZ, curvature < 5
  n = 122946 

  Weighted least-squares fit:  Y = 92.9 + 0.364 X  + -0.00051 X**2 
     at X = 100, Y = 124.2 
     effective RMSE xy = 129.4 

slope versus dZ, curvature < 15
  n = 453800 

  Weighted least-squares fit:  Y = 91.6 + 0.368 X  + -0.00107 X**2 

curvature versus dZ, slope < 10
  n = 20060 
  X=0, Y = 100.63 +/- 45.96 
  Weighted least-squares fit:  Y = 92.8 + 1.685 X  + -0.06219 X**2 


Number of samples 1931094
Max dz = 900
Mean dz = 97
RMS dz = 117.65627905
100cm = 51.5295992841 percentile value of dz