curvature versus slope
  n = 1811975 
  X=0, Y = 9.68 +/- 8.13 
  Weighted least-squares fit:  Y = 12.7 + 4.768 X  + -0.05597 X**2 

slope versus dZ, curvature < 5
  n = 923914 
  X=0, Y = 12.98 +/- 8.72 
  Weighted least-squares fit:  Y = 12.9 + 0.054 X  + 0.00281 X**2 
     at X = 100, Y = 46.4 
     effective RMSE xy = 70.0 

slope versus dZ, curvature < 15
  n = 1449505 
  X=0, Y = 13.54 +/- 9.03 
  Weighted least-squares fit:  Y = 12.9 + 0.114 X  + 0.00222 X**2 

curvature versus dZ, slope < 10
  n = 1069036 
  X=0, Y = 13.29 +/- 8.46 
  Weighted least-squares fit:  Y = 12.7 + 0.993 X  + 0.06748 X**2 


Number of samples 1827469
Max dz = 800
Mean dz = 15
RMS dz = 25.0599281723
100cm = 99.0512561362 percentile value of dz