curvature versus slope
  n = 630825 
  X=0, Y = 5.15 +/- 4.05 
  Weighted least-squares fit:  Y = 6.5 + 5.088 X  + -0.05780 X**2 

slope versus dZ, curvature < 5
  n = 489206 
  X=0, Y = 6.59 +/- 6.85 
  Weighted least-squares fit:  Y = 4.1 + 0.525 X  + -0.00213 X**2 
     at X = 100, Y = 35.3 
     effective RMSE xy = 55.1 

slope versus dZ, curvature < 15
  n = 588513 
  X=0, Y = 6.64 +/- 6.87 
  Weighted least-squares fit:  Y = 4.7 + 0.493 X  + -0.00131 X**2 

curvature versus dZ, slope < 10
  n = 537843 
  X=0, Y = 5.15 +/- 4.64 
  Weighted least-squares fit:  Y = 4.8 + 2.219 X  + -0.02545 X**2 


Number of samples 633757
Max dz = 900
Mean dz = 7
RMS dz = 23.0217288664
100cm = 99.4961791349 percentile value of dz