THE land-sea interface is one of the most complex areas of management in the world consisting of both the marine and terrestrial environments. The coastal zone is also home to an increasing number of activities, rights and interests. Population along the coastline is continuously increasing, bringing about new pressures on the fragile eco-system of the coastal zone. This has brought with it an increased need to more effectively and efficiently manage this area to meet the economic, environmental and social outcomes of sustainable development.
In this respect, Coastal Zone Management (CZM) initiatives are turning to more integrated strategies worldwide, attempting to harmonise economic, social and environmental objectives, similar to the better-developed land use management frameworks of many urban areas. In coastal areas however, the diversity of interests, some terrestrial and some marine, compounds the issue. Integrated Coastal Zone Management (ICZM) recognises that the coastal resources management situation is unique; that is, it differs greatly from management of either land or water resources, being a combination of both (Bartlett et al. 2004).

It has been established that access to spatial data aids in decision making for management and administration .In response to this situation, on land, Spatial Data Infrastructure (SDI) have been developed to create an environment that will enable users to access and retrieve complete and consistent spatial datasets in an easy and secure way. Within the marine environment tools such as marine cadastre can provide a means for delineating, managing and administering legally definable offshore boundaries, however there is still the need for an overarching spatial information platform to facilitate the use and administration of these tools in a holistic fashion. Currently, most of the SDI initiatives mainly restrict their attention to the landward or seaward regions with little or no consideration of coastal zones. There is the growing and urgent need to create a seamless SDI model that bridges the gap between the terrestrial and marine environments, creating a spatially enabled land-sea interface to more effectively meet sustainable development objectives.

With this in mind, this paper discusses coastal zone and spatial information management issues and the potential for adding a coastal dimension to an SDI to facilitate coastal zone management. It looks at the complexity and issues regarding management of the land-sea interface. Further it discusses the need to develop a seamless SDI as an enabling platform to increase the efficiency and effectiveness of management across regions and disciplines.

On land issues and challenges such as data interoperability and data integratability have been identified as major issues. However, there are more issues facing marine environment as it is highly dynamic with 4D boundaries and thus natural resources or features are more likely to move with time which leads to poor accuracy, precision, consistency and completeness of marine spatial data. These difficulties compound in the coastal zone, as it is both the on and offshore environments combined and interrelated.

As the interface between marine and terrestrial environments, coasts have diverse and ever increasing conflicting pressures and demands requiring effective administration and management. To improve management of the coastal zone, there needs to be access and interoperability of both marine and terrestrial spatial data.

However the need to effectively manage the coastal zone as well as the need for interoperable data between the three environments (land, coast, marine) requires a management system that incorporates them all. This has been recognised through the development of integrated coastal management (Gillespie et al. 2000), an initiative that aims to combine management of the coastal zone, spatially, institutionally, and ecologically. Figure 1 shows the conceptual demonstration of issues and challenges of the land, coast, and marine environments. It implies the need for overarching spatial information framework to facilitate the management of the whole environment.