curvature versus slope
  n = 1207992 
  X=0, Y = 11.22 +/- 8.05 
  Weighted least-squares fit:  Y = 15.7 + 4.635 X  + -0.05393 X**2 

slope versus dZ, curvature < 5
  n = 559593 
  X=0, Y = 30.07 +/- 8.41 
  Weighted least-squares fit:  Y = 28.4 + 0.312 X  + 0.00111 X**2 
     at X = 100, Y = 70.7 
     effective RMSE xy = 101.8 

slope versus dZ, curvature < 15
  n = 882674 
  X=0, Y = 30.07 +/- 8.41 
  Weighted least-squares fit:  Y = 28.3 + 0.338 X  + 0.00121 X**2 

curvature versus dZ, slope < 10
  n = 584847 
  X=0, Y = 29.98 +/- 11.66 
  Weighted least-squares fit:  Y = 29.7 + 0.259 X  + 0.13320 X**2 


Number of samples 1226180
Max dz = 900
Mean dz = 38
RMS dz = 60.2660766933
100cm = 94.557079711 percentile value of dz