curvature versus slope
  n = 762675 
  X=0, Y = 79.17 +/- 22.98 
  Weighted least-squares fit:  Y = 82.8 + 0.792 X  + -0.00732 X**2 

slope versus dZ, curvature < 5
  n = 8249 

  Weighted least-squares fit:  Y = -25.2 + 1.657 X  + -0.00239 X**2 
     at X = 100, Y = 116.6 
     effective RMSE xy = 178.8 

slope versus dZ, curvature < 15
  n = 83796 

  Weighted least-squares fit:  Y = -40.7 + 3.016 X  + -0.01331 X**2 

curvature versus dZ, slope < 10
  n = 42 

  Weighted least-squares fit:  Y = 5.0 + 1.510 X  + -0.03826 X**2 


Number of samples 778624
Max dz = 900
Mean dz = 107
RMS dz = 173.323397151
100cm = 66.8218549647 percentile value of dz