curvature versus slope
  n = 610642 
  X=0, Y = 7.04 +/- 6.22 
  Weighted least-squares fit:  Y = 8.8 + 4.563 X  + -0.05127 X**2 

slope versus dZ, curvature < 5
  n = 417109 
  X=0, Y = 6.98 +/- 4.23 
  Weighted least-squares fit:  Y = 5.9 + 0.292 X  + -0.00006 X**2 
     at X = 100, Y = 34.5 
     effective RMSE xy = 53.4 

slope versus dZ, curvature < 15
  n = 531026 
  X=0, Y = 7.24 +/- 4.55 
  Weighted least-squares fit:  Y = 6.3 + 0.285 X  + 0.00073 X**2 

curvature versus dZ, slope < 10
  n = 493421 
  X=0, Y = 6.74 +/- 4.23 
  Weighted least-squares fit:  Y = 6.9 + 0.606 X  + 0.03844 X**2 


Number of samples 616240
Max dz = 900
Mean dz = 10
RMS dz = 24.248711306
100cm = 98.9739387252 percentile value of dz