curvature versus slope
  n = 35022 
  X=0, Y = 5.92 +/- 3.93 
  Weighted least-squares fit:  Y = 4.0 + 6.348 X  + -0.11306 X**2 

slope versus dZ, curvature < 5
  n = 27528 
  X=0, Y = 12.66 +/- 10.52 
  Weighted least-squares fit:  Y = 14.1 + 0.219 X  + 0.00686 X**2 
     at X = 100, Y = 104.7 
     effective RMSE xy = 162.9 

slope versus dZ, curvature < 15
  n = 33485 
  X=0, Y = 12.80 +/- 10.57 
  Weighted least-squares fit:  Y = 12.8 + 0.487 X  + 0.00154 X**2 

curvature versus dZ, slope < 10
  n = 30476 
  X=0, Y = 14.83 +/- 7.96 
  Weighted least-squares fit:  Y = 15.2 + -0.249 X  + 0.20328 X**2 


Number of samples 35104
Max dz = 700
Mean dz = 14
RMS dz = 19.5448202857
100cm = 99.7436189608 percentile value of dz