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Y. Li, H. Huang, G. Chi, Y. Cao:
"An Extension of Spatial Functionality for SVG Specification";
Talk: International Conference on Scalable Vector Graphics, Nuremberg, Germany; 2008-08-26 - 2008-08-28; in: "Proceedings of SVG Open 2008", (2008).

The main characteristics of GIS functionality are the definitions of spatial position, the spatial analysis and symbols representation but SVG specification is focused on graphic representation which is not involved in such a series of the functions.

This paper introduces representing, positioning and analyzing vector map of spatial information on the Web using Scalable Vector Graphics (SVG) based on the spatial characteristics. In this point, it covers a design of SVG spatial representing model, SVG topology model, SVG Symbol base and visualizing database structure; a formal description of the objects including point, curve, polygon, relations between them and attributes related in the models and the database; and a creation of module functions of geographical coordinate transform, topology operators, basic spatial analyzing operators and SVG visualizing database in order to support the spatial position, spatial query and spatial analysis of GIS main functionalities with SVG. And it also emphasizes the importance of symbols representation of the spatial information and gives a solution of concurrent markup issue which is a common case to represent more than one attributes on one point or coordinate for overlapping hierarchies and visualizing concurrent in spatial representation. Taking example of filling both color and symbols with a centriod of polygon or two languages connected to one point etc, it is proved that the effect of the concurrent markup solution for SVG.

By the experiments and comparison with other technologies for similar purposes, these algorithms designed can be used not only to implement the spatial query like accessing spatial geometric elements and attributes, map symbols representation, spatial measurement and spatial direction definition but also to create the spatial topological operators such as `TOUCH´, `CROSS´, `DISJOINT´, `WITHIN´ and `OVERLAP´ for basic spatial relation analysis and to define the topology judging operators such as `BUFFER´, `INTERSECTION and `UNION´ operators for spatial overlapping analysis. At same time, these functions developed with JAVA Script it can be used as an extension of SVG Specification. Finally, these approaches were implemented and supported to create a software platform called `Spatial Information Service System´ which focus on the integration and analysis with multiply sources of spatial information as a delivering and serving platform for various applications in different fields.

SVG-based Spatial Information analysis, topological representation, SVG geographical projection, symbols representation