curvature versus slope
  n = 264628 
  X=0, Y = 8.65 +/- 6.60 
  Weighted least-squares fit:  Y = 10.0 + 4.626 X  + -0.05061 X**2 

slope versus dZ, curvature < 5
  n = 156877 
  X=0, Y = 21.98 +/- 11.42 
  Weighted least-squares fit:  Y = 17.7 + -0.085 X  + 0.00403 X**2 
     at X = 100, Y = 49.5 
     effective RMSE xy = 72.7 

slope versus dZ, curvature < 15
  n = 226879 
  X=0, Y = 21.28 +/- 11.04 
  Weighted least-squares fit:  Y = 17.0 + -0.000 X  + 0.00361 X**2 

curvature versus dZ, slope < 10
  n = 193100 
  X=0, Y = 18.97 +/- 11.23 
  Weighted least-squares fit:  Y = 18.7 + -0.670 X  + 0.18998 X**2 


Number of samples 265276
Max dz = 900
Mean dz = 19
RMS dz = 53.6842621259
100cm = 99.0278050031 percentile value of dz