curvature versus slope
  n = 344946 
  X=0, Y = 10.62 +/- 9.10 
  Weighted least-squares fit:  Y = 14.6 + 4.702 X  + -0.05533 X**2 

slope versus dZ, curvature < 5
  n = 202172 
  X=0, Y = 7.50 +/- 5.37 
  Weighted least-squares fit:  Y = 6.7 + 0.317 X  + 0.00060 X**2 
     at X = 100, Y = 44.5 
     effective RMSE xy = 69.0 

slope versus dZ, curvature < 15
  n = 272630 
  X=0, Y = 7.91 +/- 5.64 
  Weighted least-squares fit:  Y = 7.1 + 0.319 X  + 0.00080 X**2 

curvature versus dZ, slope < 10
  n = 211080 
  X=0, Y = 8.09 +/- 5.31 
  Weighted least-squares fit:  Y = 7.3 + 1.511 X  + 0.07005 X**2 


Number of samples 348435
Max dz = 900
Mean dz = 14
RMS dz = 40.8778668719
100cm = 98.3956835565 percentile value of dz