curvature versus slope
  n = 101807 
  X=0, Y = 36.20 +/- 21.13 
  Weighted least-squares fit:  Y = 53.6 + 2.216 X  + -0.02458 X**2 

slope versus dZ, curvature < 5
  n = 23321 

  Weighted least-squares fit:  Y = 80.6 + -0.518 X  + 0.01001 X**2 
     at X = 100, Y = 128.9 
     effective RMSE xy = 158.0 

slope versus dZ, curvature < 15
  n = 41287 

  Weighted least-squares fit:  Y = 79.2 + -0.392 X  + 0.00921 X**2 

curvature versus dZ, slope < 10
  n = 3940 
  X=0, Y = 84.83 +/- 28.34 
  Weighted least-squares fit:  Y = 84.3 + 1.403 X  + -0.55902 X**2 


Number of samples 102785
Max dz = 900
Mean dz = 101
RMS dz = 137.113092008
100cm = 56.165782945 percentile value of dz