curvature versus slope
  n = 268051 
  X=0, Y = 9.82 +/- 5.61 
  Weighted least-squares fit:  Y = 8.9 + 4.385 X  + -0.04726 X**2 

slope versus dZ, curvature < 5
  n = 155016 
  X=0, Y = 7.61 +/- 4.30 
  Weighted least-squares fit:  Y = 6.8 + 0.551 X  + -0.00300 X**2 
     at X = 100, Y = 31.9 
     effective RMSE xy = 48.9 

slope versus dZ, curvature < 15
  n = 232408 
  X=0, Y = 8.69 +/- 5.24 
  Weighted least-squares fit:  Y = 7.6 + 0.479 X  + -0.00058 X**2 

curvature versus dZ, slope < 10
  n = 161585 
  X=0, Y = 9.63 +/- 6.09 
  Weighted least-squares fit:  Y = 8.9 + 1.325 X  + 0.05537 X**2 


Number of samples 269465
Max dz = 900
Mean dz = 13
RMS dz = 44.418464629
100cm = 98.9223090197 percentile value of dz