curvature versus slope
  n = 608666 
  X=0, Y = 9.56 +/- 7.19 
  Weighted least-squares fit:  Y = 10.2 + 4.741 X  + -0.05210 X**2 

slope versus dZ, curvature < 5
  n = 387912 
  X=0, Y = 9.97 +/- 6.58 
  Weighted least-squares fit:  Y = 8.8 + 0.249 X  + 0.00074 X**2 
     at X = 100, Y = 41.1 
     effective RMSE xy = 63.0 

slope versus dZ, curvature < 15
  n = 536568 
  X=0, Y = 10.22 +/- 6.70 
  Weighted least-squares fit:  Y = 8.9 + 0.256 X  + 0.00111 X**2 

curvature versus dZ, slope < 10
  n = 434597 
  X=0, Y = 9.76 +/- 6.22 
  Weighted least-squares fit:  Y = 9.5 + 0.424 X  + 0.11733 X**2 


Number of samples 613394
Max dz = 700
Mean dz = 12
RMS dz = 24.7991935353
100cm = 99.1581267505 percentile value of dz