curvature versus slope
  n = 416524 
  X=0, Y = 21.58 +/- 16.04 
  Weighted least-squares fit:  Y = 28.0 + 3.214 X  + -0.03315 X**2 

slope versus dZ, curvature < 5
  n = 117158 
  X=0, Y = 56.78 +/- 41.90 
  Weighted least-squares fit:  Y = 45.7 + -0.347 X  + 0.00376 X**2 
     at X = 100, Y = 48.6 
     effective RMSE xy = 26.0 

slope versus dZ, curvature < 15
  n = 250197 
  X=0, Y = 56.78 +/- 41.90 
  Weighted least-squares fit:  Y = 48.9 + -0.482 X  + 0.00475 X**2 

curvature versus dZ, slope < 10
  n = 92463 
  X=0, Y = 40.57 +/- 29.85 
  Weighted least-squares fit:  Y = 41.3 + 2.143 X  + -0.04691 X**2 


Number of samples 419450
Max dz = 900
Mean dz = 36
RMS dz = 51.4490038776
100cm = 96.0505423769 percentile value of dz