curvature versus slope
  n = 602629 
  X=0, Y = 14.49 +/- 11.64 
  Weighted least-squares fit:  Y = 34.0 + 3.111 X  + -0.03444 X**2 

slope versus dZ, curvature < 5
  n = 114165 
  X=0, Y = 6.41 +/- 3.84 
  Weighted least-squares fit:  Y = 8.1 + 0.262 X  + 0.00187 X**2 
     at X = 100, Y = 53.0 
     effective RMSE xy = 82.3 

slope versus dZ, curvature < 15
  n = 175796 
  X=0, Y = 6.79 +/- 3.77 
  Weighted least-squares fit:  Y = 7.8 + 0.404 X  + 0.00089 X**2 

curvature versus dZ, slope < 10
  n = 99355 
  X=0, Y = 9.02 +/- 5.96 
  Weighted least-squares fit:  Y = 8.3 + 2.653 X  + -0.02118 X**2 


Number of samples 606529
Max dz = 900
Mean dz = 42
RMS dz = 71.2530701093
100cm = 88.9011077789 percentile value of dz