Facilitating land-sea interface through seamless SDI
SHEELAN VAEZ, ABBAS RAJABIFARD, IAN P WILLIAMSON
Table 1 outlines the current institutional, policy and technical marine/coastal issues and their consequent effect.
Based on the above table, the institutional issues such as collecting and storing various spatial datasets by different organisations result difficulty in finding and obtaining datasets also existing of different data formats, refrence frames and lack of metadata leads to lack of interoperability of different datasets. Accordingly this complex, fragmented regulating framework for marine and coastal management causes the inability to adequately handle the pressure of different activities and stakeholders within the coastal zone. Therefore there is a need for a framework to better respond to these issues and their consequent effects.
As a result, incorporation of marine and coastal regions within global, national and regional SDIs will bring substantial additional benefits of integration, standardisation and interoperability of technologies, enabling better policy formulation, monitoring and enforcement, often reaching beyond the coastal zone itself (Bartlett et al. 2004). A more integrated and holistic approach to management of coastal and marine environments would be facilitated by the extension of the SDI on a seamless platform. This would promote data sharing and communication between organisations thus facilitating better decision-making involving marine and coastal spatial information.
For modelling the coastal zone, there is likely to be one source for the land, another for the sea and potentially other subsidiary datasets straddling both. In these cases there will inevitably be some data interoperability issues. One of the typical problems is differences in scale when trying to join together data captured at different scales. Seaward datasets which are often at smaller scales simplifying the geometry of the features while landward datasets are large scale with much more complexity and greater density of details. This results in a disparity in the feature common to both zones. Another barrier to a seamless SDI is in different projections regarding land and sea data, which creates a problem in defining the parameters required for transformations (Gomm 2004).
Common standards and well documented metadata are essential for data discovery, management and compatibility within a SDI.. In this respect the IHO has an important role to play in developing the appropriate standards needed for its hydrographic and cartographic applications, in close cooperation with appropriate organisations responsible for standardisation, such as ISO. As an example the IHO S-57 standard, although limited in scope and implementation, provides important compatibility for data sharing in the hydrographic information community. The next edition of the standard will not be a standard just for hydrography, but will have manageable flexibility that can accommodate change and facilitate interoperability with other GIS standards. It will also allow hydrographic offices to use other sources of geospatial data. The next edition of S-57 (which will become S-100), is being based on the ISO/TC211 base standard. This will facilitate the development of additional products and services “other than for navigation” requirements. Funding for the development, maintenance and dissemination methods adapted to user needs and new technology of this Infrastructure, is a very crucial issue, which of course will depend on national policies for recovery or not of the necessary funds (Maratos 2007).
A seamless infrastructure was endorsed by the UN as part of the International Workshop on Administering the Marine Environment held in Kuala Lumpur, Malaysia, 2004 (Rajabifard et al. 2005). It was recommended that a marine cadastre act as a management tool within a marine SDI as an extension to NSDI’s across Asia-Pacific. Recently, a recommendation of the 17th United Nations Regional Cartographic Conference for Asia and the Pacific (UNRCC-AP) in Bangkok further supported the inclusion and development of a marine administration component as part of a seamless SDI to “ensure a continuum across the coastal zone” (UNRCC-AP 2006).