longest horizontal extent of a region to be mapped. The mean vari- 

 ance between the mapped curves and that specified after 120 itera- 

 tions with n=140 was 4.4 square kilometers. The level of vari- 

 ance achieved indicates that the bicurve fitting equations are 

 marginally successful in mapping this enlarged region. The change 

 in the variance level over the last 10 iterations and limits on 

 computer time were the bases for terminating the iterative procedure. 

 The convergence criteria can be satisfied either by a shorter hori- 

 zontal extent or smoother curves for a longer region. 



49 



