curvature versus slope
  n = 463321 
  X=0, Y = 14.01 +/- 8.54 
  Weighted least-squares fit:  Y = 18.0 + 4.224 X  + -0.04749 X**2 

slope versus dZ, curvature < 5
  n = 217501 
  X=0, Y = 10.52 +/- 4.05 
  Weighted least-squares fit:  Y = 8.9 + 0.434 X  + 0.00067 X**2 
     at X = 100, Y = 59.0 
     effective RMSE xy = 91.7 

slope versus dZ, curvature < 15
  n = 339106 
  X=0, Y = 10.52 +/- 4.05 
  Weighted least-squares fit:  Y = 9.1 + 0.483 X  + 0.00085 X**2 

curvature versus dZ, slope < 10
  n = 154311 
  X=0, Y = 11.73 +/- 7.83 
  Weighted least-squares fit:  Y = 11.4 + 1.387 X  + 0.11575 X**2 


Number of samples 472170
Max dz = 900
Mean dz = 25
RMS dz = 55.9732078766
100cm = 95.27987801 percentile value of dz