In recent years the World Wide Web has become a popular vehicle for information distribution and geographic information systems (GIS) are rapidly evolving and adapting to this new environment.

The main constraint for building true interoperable distributed geographic information systems is the lack of any standard exchange mechanism between those GISes. Recent efforts by the Open GIS Consortium have resulted in several specifications to solve these problems. The Geographic Markup Language (GML) is one example of a proposed standard.

GML is an XML (eXtensible Markup Language) encoding for the transport over the Internet and the storage of geographic information, including both geometry and properties of geographic features. The parsing techniques have performance issues since the size of GML documents may be potentially huge.

Mobile Computing devices (PDA) have evolved very fast over the last years. They are no longer seen as task supporting devices, such as electronic personal information managers, but as powerful new tools to manage all kinds of data.

This evolution forced a shift on system development paradigms, requiring new ways to reconcile replicas stored on different devices, with a common database. This synchronization poses several challenges.

The main focus of our study is to evaluate how to use Mobile Computing devices on Geographic Information Systems, mainly for the purpose of updating georreferenced data.

This work focuses on the development of an application for mobile devices, which allows the updating of georreferenced data, a Palm device was chosen to demonstrate this. The GML standard is evaluated and used thoroughly on this.

This standard was found useful and should be used to transform data among different applications. We concluded that mobile devices can be used (as long as code is developed taking into account the specific constraints) to develop applications existing up to now only on larger systems.