ISPRS, Vol.34, Part 2W2, “Dynamic and Multi-Dimensional GIS", Bangkok, May 23-25, 2001 
113 
lents in the 
lansas city, 
/Vide Area 
I. 6, No. 4, 
iple Moving 
3s”, UCGE 
eering, The 
D. Stowers 
isers”. GPS 
FEDERATED SPATIAL DATABASES AND INTEROPERABILITY 
Jianya GONG Yandong WANG 
National Laboratory for Information Engineering in Surveying, Mapping and Remote Sensing, 
Wuhan University 
129 Luoyu Road, Wuhan, China, 430079 
{jgong, wyd}@rcgis.wtusm.edu.cn 
Key words: Federated, Spatial Databases, Interoperability 
CLC number: P237.9 TP311.13 TP393 TN711 
Abstract 
It is a period of information.explosion. Especially for spatial information science, information can be acquired through 
many ways, such as man-made planet, aeroplane, laser, digital photogrammetry and so on. Spatial data sources are 
usually distributed and heterogeneous. Federated database is the best resolution.for the share and interoperation of 
spatial database. In this paper, the concepts of federated database and interoperability are introduced. Three 
heterogeneous kinds of spatial data, vector, image and DEM are used to create integrated database. A data model 
of federated spatial databases is given. 
1. Introduction 
The cost of the spatial data acquisition is high, and 
the cost of maintaining the spatial data is even high. 
How to use and share spatial data is very important 
for the development of spatial data infrastructure. A 
common method for spatial data sharing is to use_a 
spatial data standard, such as US Spatial Data 
Transfer Standard (SDTS), Chinese National Geo 
spatial Data Transfer Format (CNSDTF). 
Fig. 1 Data sharing using a transfer standard 
The spatial data transfer standards generally have 
the following characters: 
•Integrality 
Integrality means that Geo-Spatial data transfer 
format should include all GIS information without any 
loss during the transfer. 
•Simplicity 
Geo-Spatial data transfer standard should be 
simple and easy to understand. 
•Compatibility 
Spatial data transfer standard should be 
compatible in different kinds of GISs and different 
sources of spatial information. 
•Extensibility 
Because of the cognitive limitation to spatial 
phenomena, the current spatial data transfer 
standard may be unsuited in the future. So it should 
be expandable and compatible with the former data 
and software packages. 
Spatial data transfer standard is a kind of type for 
spatial data interoperability. But spatial data transfer 
standard generally defines geometrical primitives and 
do not define the level of semantic. Only 
homogeneity spatial data can exchange data through 
the spatial data standards. How to integrate 
heterogeneous spatial databases and exchange data 
between distributed multi-databases is a new project. 
An ideal solution for the problem is the use of 
federated database systems. 
This paper is organized as follows. Section 2 
describes the concepts of federated database and its 
interoperability. Section 3 introduces three kinds of 
heterogeneous spatial data. In section 4, a data 
model of federated spatial databases is given. 
2. The Concepts of Federated Database and 
Interoperability 
A federated system consists of the combination of