GML-based representation architecture for digital geo-science GIS layers: a case study using Korea digital geologic map sets

Now most Internet map services are provided on the Web, but most of those approaches depend on images in graphic format. These types of image format require relatively large-sized files, and have some problems with data transport and storage on the Web. In addition, as the meaning of the data is not captured as parts of the data itself, data translation, when it happens, must then be accompanied by painstaking manual process to restore the meaning. To overcome these problems, GML (Geographic Markup Language) has developed as the Web standard format of geographic information. Although GML focus on describing the geographic information as the type of XML (eXtensible Markup Language), there are few cases applied to digital geologic maps till now. In this study, Internet mapping of a Korean digital geologic map was accomplished using GML as a case study. Digital geologic map sets consist of geologic boundary, geo-text, fault, cross section, lithology and other complex items to represent geo-based attributes. Each layer was described to both spatial and non-spatial information using GML profile proposed by OGC (open GIS Consortium, Inc.). Spatial and non-spatial information were described as geometry of GML and properties of geographic features, respectively. The geographic information described by GML was transformed into SVG (Scalable Vector Graphics), one of the XML standards for graphic format. Vector maps can be visualized via the Internet without proprietary software on the Web browsers. SVG-enabled browsers allow users to control their view with zoom and pan as they do so in GIS software. As the content and the representation of the geographic information were separated in the Internet mapping process of digital map, it is possible to produce multiple representation about the same geographic information and the dynamic customization on user's need, and the spatial analysis on the Web. Conclusively, GML-base geologic map produced in this study can be transfer rapidly without loss of the meaning and degrading on the Web. So it can be effectively utilized to not only Internet map services but also LBS (Location Based Services) such as PDA or a mobile platform.