curvature versus slope
  n = 112908 
  X=0, Y = 20.06 +/- 14.33 
  Weighted least-squares fit:  Y = 37.0 + 2.945 X  + -0.03259 X**2 

slope versus dZ, curvature < 5
  n = 28616 
  X=0, Y = 7.35 +/- 0.58 
  Weighted least-squares fit:  Y = 4.5 + 0.415 X  + -0.00134 X**2 
     at X = 100, Y = 32.5 
     effective RMSE xy = 50.6 

slope versus dZ, curvature < 15
  n = 48729 
  X=0, Y = 7.35 +/- 0.58 
  Weighted least-squares fit:  Y = 5.0 + 0.439 X  + -0.00099 X**2 

curvature versus dZ, slope < 10
  n = 14441 
  X=0, Y = 6.36 +/- 3.88 
  Weighted least-squares fit:  Y = 6.4 + 1.424 X  + 0.01273 X**2 


Number of samples 113685
Max dz = 900
Mean dz = 33
RMS dz = 99.2068546019
100cm = 94.1390684787 percentile value of dz