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lat/lon, Kupang-NTT, Indonesia markus.lupp@lat-lon.de  Since the formation of the Open Geospatial Consortium (OGC) in 1994 its standardisation process had an enormous impact on the geospatial industry all over the world. The first year of OGC's work brought the Simple Feature Specifications that were the prerequisite for the storage of geospatial data in relational databases. This defined a big step forward for all kinds of spatial applications. Next came the OGC Web Services, their most prominent ones being Web Map Service (WMS, access to digital maps) and Web Feature Service (WFS, access to object-modelled spatial data). These services are essential for the development of interoperable Spatial Data Infrastructures (SDI) that are being set up in all parts of the world. WMS and WFS allow standardized access to spatial data, yet the first step of their usage is finding them in the first place. For this task Catalogue Services are necessary which are metadata registries for data and services. WMS, WFS and Catalogue Services (web-based Catalogue Services are abbreviated CS-W) define the base components SDI. One could say the build-up of SDI happens from two directions, one being the top-down initiatives that are set up on the state level to define National Spatial Data Infrastructure (NSDI). Besides, OGC standards are taken up by all kinds of projects that can form the base of the NSDI, this is the bottom-up direction. During last years both directions could be observed in South-East Asia, showing good development chances of SDI. On international level, there are a number of initiatives defining requirements and needs for application of geospatial standards. The most important are the Global Spatial Data Infrastructure (GSDI) and the United Nations Spatial Data Infrastructure (UNSDI). In Asian region Digital Asia makes use of the OGC standards WMS, WFS and WCS (Web Coverage Service, allows access to raster and image data) for geodata exchange. Another cross-border initiative is Sentinel Asia, a voluntary initiative for establishing a disaster management support system for the Asia-Pacific region. Sentinel Asia will use the OGC-based server infrastructure of digital Asia and therefore is another example of a system using WMS, WFS and WCS. The following article highlights some observations regarding the uptake of OGC standards in geospatial projects in Indonesia, Malaysia and Thailand. Covering such a large area, the article cannot be (and is not intended to be) comprehensive in regard to geospatial projects making use of OGC standards, but rather is a spotlight that shows the trend towards interoperable geospatial web services.  Fig.1Clearinghouse of the Indonesian IDSN NATIONAL SDI INITIATIVES AND EXEMPLAR PROJECTS Thailand, Malaysia and Indonesia are developing National Spatial Data Infrastructures (NSDI) with a number of similarities but also differences. A similarity of the approaches is that all three initiatives are using OGC standards to some degree. Another similarity that is shared with all NSDIs worldwide is that the first starting components are a metadata information system ("search engine") for geospatial data and interactive maps. Besides these top-down SDI building approaches, all three countries show a number of OGC-standardsbased projects. The following examples only discuss technical aspects of SDI building. All mentioned SDI initiatives also have significant non-technical aspects such as political frameworks and directives for harmonisation of geodetic and geodata standards. INDONESIA The initiative for an Indonesian NSDI was formally started in 1993 with its first development steps focussed on development of a national standard exchange format, development of a data dictionary and a web-based example application. By now a portal of the Infrastruktur Data Spasial Nasional (IDNS) is available that is based on GeoNetwork OpenSource (see fig. 2). This web-portal software supports a number of metadata standards such as CSDGM, ISO 19115 and Dublin Core. Besides, it supports the OGC Catalogue Services interface and the WMS interface.  Fig.2Geoportal of the City of Samarinda in Eastern Kalimantan This kind of portal allows access to distributed metadata using catalogue service interfaces, so a user can find out what kind of spatial datasets already exist. It is also possible to visualize the data, either in a standalone map viewer or as an integrated one. Such a viewer is able to display the data of a catalogue search, at least if a map service is available for the data at interest. The instance set up as part of IDSN allows to query a number of catalogue services that were set up already by different Indonesian institutions. Another interesting example of a WMS-based geoportal was (so far as a prototype) developed by Samarinda City (fig. 3). This city map portal is much more focused in its usage and available data. It shows a number of geodata sets of the city and its surrounding. This portal also was developed using Open Source software and is fully WMS-based, which means it uses the three operations defined by the WMS standard (GetCapabilities, GetMap and GetFeatureInfo) as its internal interfaces. The map portal is integrated to a high degree in the overall web portal of Samarinda.  Fig.3The myGDI MapViewer showing local data combined with the DENIS WMS MALAYSIA As the Indonesian one, Malaysia's NSDI initiative - called myGDI - shows as a first visible output a portal with metadata query facilities and a web-based mapviewer (see fig. 3). This map viewer is not a native WMSbased application but it nonetheless supports the OGC standard WMS. In Figure 3 a map can be seen that displays geodata from the viewer itself combined with layers from the OGC-compliant DENIS WMS. The Malaysian geoportal has many more functionalities than mere web mappings, such as registration and authentication of users and data download. All screenshots were taken using anonymous access. Malaysia shows a good number of projects, many of academic nature, working with OGC standards. Many of these projects evaluate the usage of Open Source projects such as deegree, UMN MapServer, Map- Builder or GeoServer for SDI building.  Fig.4ThaiGOS portal with added WMS data THAILAND ThaiSDI, as the SDI intiative in Thailand is called, uses OGC standards conceptually to a high degree. The first phase of ThaiSDI - the metadata clearinghouse - implemented the OGC Services WMS, WFS and Catalogue Service. The online map browser that can be seen in Figure 1 is a completely OGC WMS based Viewer. In the figure data from the WMS of the portal itself is combined with data from an external WMS. On the left and right of the GUI, results of GetCapabilities and GetFeatureInfo-Requests can be seen. The GetCapabilities windows shows the layers that a WMS offers and allows to switch these layers on and off (upper left in the screenshot). The GetFeature- Info window on the right enables users to see attribute data of geoobjects that are selected. Besides this initiative, there is a number of other projects in Thailand that are working with OGC standards. Many of these projects are in the context of disaster mapping and management and therefore often have a cross-border setting. There also is an increasing number of studies about usage of Open Source software for SDI building. These studies mainly focus on software able to support OGC WMS and WFS. SUMMARY The usage of OGC-standards in Indonesia, Thailand and Malaysia by now is comparable with the situation in Europe and North America. All three countries show well-developed NSDI initiatives that are technically at least partly based on standards such as WMS and Catalogue Service. A large number of additional projects exist on different levels and in academia, these being mainly focussed on WMS. Not surprisingly there still are few WFS-based applications. The reasons for this phenomenon is that WFStechnology is much more complex than WMS, especially in its regard to interoperability. WFS needs well-defined semantic data models that are then translated into GML application schemata. The process of defining and implementing these data model is long as it requires a common understanding of an application domain by all stakeholders. Examples for such GML application schemas are CityGML that is developed by members of the OGC itself for 3D city models (buildings, streets, trees etc.) and a number of local (mostly national) data models for different application domains such as cadastral data or data for urban and town planning. Another application area for WFS is the creation of gazetteers which are needed for navigation and queries using geographic identifiers. Development of standardised gazetteers often is a step following the setup of Catalogue Services and WMS instances. A second (or third) step in SDI initiatives also is the usage of Symbology Encoding (SE) and Styled Layer Descriptor (SLD) for standardization of symbology rules. As standardised symbology needs well-defined data models, it might still take some time until we see the widespread use of these specifications. Many of the projects using OGC standards are making use of Open Source software, a trend that also can be seen in other parts of the world. One of the main reasons for this effect is that the geospatial Open Source community seems to embrace open standards to a high degree. Page 1 of 1
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