curvature versus slope
  n = 1038976 
  X=0, Y = 23.48 +/- 19.20 
  Weighted least-squares fit:  Y = 42.8 + 2.577 X  + -0.02643 X**2 

slope versus dZ, curvature < 5
  n = 35426 

  Weighted least-squares fit:  Y = 7.9 + 0.208 X  + 0.00080 X**2 
     at X = 100, Y = 36.7 
     effective RMSE xy = 56.4 

slope versus dZ, curvature < 15
  n = 131874 

  Weighted least-squares fit:  Y = 9.5 + 0.185 X  + 0.00155 X**2 

curvature versus dZ, slope < 10
  n = 25104 
  X=0, Y = 8.53 +/- 6.17 
  Weighted least-squares fit:  Y = 9.1 + 1.067 X  + 0.05573 X**2 


Number of samples 1050839
Max dz = 900
Mean dz = 44
RMS dz = 69.9070811864
100cm = 87.6310262562 percentile value of dz