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).
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