support the implementation of object oriented model in an effi- 
cient way and can establish standard methods for GIS software 
engineering. 
References: 
Boudriault, G., 1987. Topology in the TIGER File. Auto Carto 
8 Proceedings, pp.258-263. 
Kim, W., 1990. Introduction to Object-Oriented Databases. The 
MIT Press Cambridge, Massachusetts. 
Molenaar, M., 1989. Single Valued Vector Maps - A Concept in 
Geographic Information Systems. Geo-Informations-System, 
Vol.2, No.1, pp.18-26. 
Adress of Authors: 
Dr. H. Yang/Dr. W. Reinhardt 
Siemens Nixdorf Informationssystem AG 
Fachzentrum Geo-Informationssystem 
Otto-Hahn-Ring 6 
D-8000 München 83 
154 
AE 
the 
tio: 
prc 
the 
inf 
tial 
log 
dat 
Frc 
gie 
tim 
ge 
gie 
shc 
the 
to | 
anc 
asp 
(or 
rea 
are 
COI 
his 
Th 
inte 
tup 
tim 
apr 
rel: 
dat 
Sto 
but