curvature versus slope
  n = 264067 
  X=0, Y = 11.81 +/- 9.34 
  Weighted least-squares fit:  Y = 17.8 + 4.140 X  + -0.04596 X**2 

slope versus dZ, curvature < 5
  n = 130940 
  X=0, Y = 11.34 +/- 6.44 
  Weighted least-squares fit:  Y = 12.5 + 0.156 X  + 0.00094 X**2 
     at X = 100, Y = 37.6 
     effective RMSE xy = 55.6 

slope versus dZ, curvature < 15
  n = 184315 
  X=0, Y = 11.15 +/- 6.10 
  Weighted least-squares fit:  Y = 12.4 + 0.155 X  + 0.00189 X**2 

curvature versus dZ, slope < 10
  n = 136314 
  X=0, Y = 14.14 +/- 10.22 
  Weighted least-squares fit:  Y = 12.2 + 0.712 X  + 0.10830 X**2 


Number of samples 266183
Max dz = 900
Mean dz = 22
RMS dz = 64.1170804076
100cm = 96.2935273853 percentile value of dz