Using SVG and XSLT for graphic representation

Using SVG and XSLT for graphic representation In this paper we will present an XML based framework that can be used to produce graphical visualisation of scientific data. The approach rather than producing ordinary histogram and function diagaram graphs, tries to represent the information in a more graphical appealing and easy to understand way. For examples the approach will give the ability to represent the temperature as the level of coulored fluid in a thermometer. The proposed framework is able to maintain the value of the datas strictly separated from the visual form of its representation (positions of element, colours, visual representation etc.). By defining appropriate data structures and expressing them using XML, the framework gives the user the ability to create graphic representations using standard SVG and XSLT. Since XML can be used for describing complex data information, we represent every level of the graphic representation with an XML structure. To describe our architecture we defined the following XML dialects, each one with different markup tags, reflecting the semantical values of the elements. Data definition level. Used to define the value of the datas that can be used in the graphic representation Data representation level. Used to define the graphic representation, it defines how the values expressed by the data definition level are represented. Both data representation and data definition files are based on a DTD to impose the constraints. Data representation level is the core of the system, and defines a powerful language for representation. Source primitives. Used to define for the source of the graphic elements, for example static file or SVG code. Modification primitives. Used to define the modifications that can affect a graphic element, for example rotation, scaling or repetition. Disposition primitives. Used to define the possible dispositions along x, y and z axes, for example to impose a order in the representation of elements. Action primitives. Used to define the possible actions that canbe activated by graphic elements for different user behaviours. For example a mouse action can activate a link to a different resource, or can change the value of any of the other primitives of the data structure, as image source or disposition, or can show a tooltip . XSLT is used to output a SVG file derived from the two files describing the graphic representation. Our aim is to provide an abstract language to be used to represent in different ways the same concept. In fact, we can link a data definition file with different data representation levels, providing different kinds and levels of complexity for the same concept. An example use could be the representation of the temperature described before, where the temperature itself could be represented either as the level of mercury in the termomether, or as the rotation of an arrow in a gauge. The transformation process is made from an XML source tree into an XML result tree, using XPath to define patterns. XSLT transformation process is based on templates, that define some actions (like adding or removing elements, or sorting them) to be performed when a part of the document matches a template. To implement some of the complex graphics operations we are using XSLT extensions that allow to perform mathematical operations. These XSLT extensions are not yet standard and require specific compliant parser, as Apache Xalan, that allows the developer to interface with Java classes in order to increase XSLT areas of application, from simple node transformations to quite complex operations

Interactive tag maps and tag clouds for the multiscale exploration of large spatio-temporal datasets

'Tag clouds' and 'tag maps' are introduced to represent geographically referenced text. In combination, these aspatial and spatial views are used to explore a large structured spatio-temporal data set by providing overviews and filtering by text and geography. Prototypes are implemented using freely available technologies including Google Earth and Yahoo! 's Tag Map applet. The interactive tag map and tag cloud techniques and the rapid prototyping method used are informally evaluated through successes and limitations encountered. Preliminary evaluation suggests that the techniques may be useful for generating insights when visualizing large data sets containing geo-referenced text strings. The rapid prototyping approach enabled the technique to be developed and evaluated, leading to geovisualization through which a number of ideas were generated. Limitations of this approach are reflected upon. Tag placement, generalisation and prominence at different scales are issues which have come to light in this study that warrant further work

WEST: A Web Browser for Small Terminals

We describe WEST, a WEb browser for Small Terminals, that aims to solve some of the problems associated with accessing web pages on hand-held devices. Through a novel combination of text reduction and focus+context visualization, users can access web pages from a very limited display environment, since the system will provide an overview of the contents of a web page even when it is too large to be displayed in its entirety. To make maximum use of the limited resources available on a typical hand-held terminal, much of the most demanding work is done by a proxy server, allowing the terminal to concentrate on the task of providing responsive user interaction. The system makes use of some interaction concepts reminiscent of those defined in the Wireless Application Protocol (WAP), making it possible to utilize the techniques described here for WAP-compliant devices and services that may become available in the near future

Linguistic Geometries for Unsupervised Dimensionality Reduction

Text documents are complex high dimensional objects. To effectively visualize such data it is important to reduce its dimensionality and visualize the low dimensional embedding as a 2-D or 3-D scatter plot. In this paper we explore dimensionality reduction methods that draw upon domain knowledge in order to achieve a better low dimensional embedding and visualization of documents. We consider the use of geometries specified manually by an expert, geometries derived automatically from corpus statistics, and geometries computed from linguistic resources.Comment: 13 pages, 15 figure