curvature versus slope
  n = 303151 
  X=0, Y = 9.62 +/- 7.60 
  Weighted least-squares fit:  Y = 13.5 + 4.449 X  + -0.04977 X**2 

slope versus dZ, curvature < 5
  n = 195866 
  X=0, Y = 5.33 +/- 3.16 
  Weighted least-squares fit:  Y = 4.5 + 0.182 X  + 0.00200 X**2 
     at X = 100, Y = 42.7 
     effective RMSE xy = 66.7 

slope versus dZ, curvature < 15
  n = 247789 
  X=0, Y = 5.40 +/- 3.19 
  Weighted least-squares fit:  Y = 4.5 + 0.248 X  + 0.00166 X**2 

curvature versus dZ, slope < 10
  n = 180360 
  X=0, Y = 4.99 +/- 3.05 
  Weighted least-squares fit:  Y = 4.5 + 1.509 X  + 0.06850 X**2 


Number of samples 308323
Max dz = 900
Mean dz = 13
RMS dz = 39.0512483795
100cm = 97.784141955 percentile value of dz