curvature versus slope
  n = 4028 
  X=0, Y = 3.64 +/- 1.80 
  Weighted least-squares fit:  Y = 3.6 + 1.013 X  + 0.19832 X**2 

slope versus dZ, curvature < 5
  n = 3877 
  X=0, Y = 47.22 +/- 26.14 
  Weighted least-squares fit:  Y = 53.6 + 2.989 X  + -0.17798 X**2 
     at X = 100, Y = -1427.3 
     effective RMSE xy = 2240.4 

slope versus dZ, curvature < 15
  n = 4012 
  X=0, Y = 47.22 +/- 26.14 
  Weighted least-squares fit:  Y = 54.4 + 2.556 X  + -0.13821 X**2 

curvature versus dZ, slope < 10
  n = 3992 
  X=0, Y = 60.38 +/- 20.34 
  Weighted least-squares fit:  Y = 60.8 + 1.815 X  + -0.19613 X**2 


Number of samples 4029
Max dz = 96
Mean dz = 58
RMS dz = 61.3921819127
100cm = 0 percentile value of dz