curvature versus slope
  n = 370420 
  X=0, Y = 18.39 +/- 13.49 
  Weighted least-squares fit:  Y = 32.2 + 3.367 X  + -0.03782 X**2 

slope versus dZ, curvature < 5
  n = 132366 
  X=0, Y = 5.18 +/- 3.09 
  Weighted least-squares fit:  Y = 8.2 + 0.298 X  + 0.00133 X**2 
     at X = 100, Y = 51.4 
     effective RMSE xy = 79.7 

slope versus dZ, curvature < 15
  n = 197236 
  X=0, Y = 5.18 +/- 3.09 
  Weighted least-squares fit:  Y = 8.0 + 0.373 X  + 0.00151 X**2 

curvature versus dZ, slope < 10
  n = 79262 
  X=0, Y = 11.37 +/- 6.90 
  Weighted least-squares fit:  Y = 10.4 + 0.913 X  + 0.07740 X**2 


Number of samples 373313
Max dz = 900
Mean dz = 34
RMS dz = 66.6708332031
100cm = 92.0083147386 percentile value of dz