curvature versus slope
  n = 1052803 
  X=0, Y = 8.02 +/- 7.03 
  Weighted least-squares fit:  Y = 6.2 + 4.566 X  + -0.05163 X**2 

slope versus dZ, curvature < 5
  n = 580985 
  X=0, Y = 10.61 +/- 7.10 
  Weighted least-squares fit:  Y = 9.5 + 0.287 X  + -0.00047 X**2 
     at X = 100, Y = 33.6 
     effective RMSE xy = 50.6 

slope versus dZ, curvature < 15
  n = 937731 
  X=0, Y = 10.89 +/- 7.31 
  Weighted least-squares fit:  Y = 10.3 + 0.247 X  + 0.00079 X**2 

curvature versus dZ, slope < 10
  n = 823049 
  X=0, Y = 10.39 +/- 6.80 
  Weighted least-squares fit:  Y = 9.9 + 1.418 X  + 0.00047 X**2 


Number of samples 1054170
Max dz = 500
Mean dz = 10
RMS dz = 15.2643375225
100cm = 99.8512573873 percentile value of dz