80' 



60' 





if 





30' 





§ 







c? 



$ 



00' 



00' 



30' 



60' 



80' 



FIGURE 13. CONTOUR OF MODEL-3 POINT-VALUE RESIDUALS (SPLINE 

 INTERPOLATION VS. TRUE VALUE) WITH A CONTOUR 

 INTERVAL OF 0.5 mgl. 



32 



