Interactive Visual Exploration of a Large Spatio-temporal Dataset: Reflections on a Geovisualization Mashup

Jo Wood, Jason Dykes, Aidan Slingsby, Keith Clarke
2007 IEEE Transactions on Visualization and Computer Graphics  
exploration of a large spatio-temporal dataset: Reflections on a geovisualization mashup. This is the published version of the paper. This version of the publication may differ from the final published version. Permanent repository link: http://openaccess.city.ac.uk/176/ Link to published version: http://dx.Abstract -Exploratory visual analysis is useful for the preliminary investigation of large structured, multifaceted spatio-temporal datasets. This process requires the selection and
more » ... on of records by time, space and attribute, the ability to transform data and the flexibility to apply appropriate visual encodings and interactions. We propose an approach inspired by geographical 'mashups' in which freely-available functionality and data are loosely but flexibly combined using de facto exchange standards. Our case study combines MySQL, PHP and the LandSerf GIS to allow Google Earth to be used for visual synthesis and interaction with encodings described in KML. This approach is applied to the exploration of a log of 1.42 million requests made of a mobile directory service. Novel combinations of interaction and visual encoding are developed including spatial 'tag clouds', 'tag maps', 'data dials' and multi-scale density surfaces. Four aspects of the approach are informally evaluated: the visual encodings employed, their success in the visual exploration of the dataset, the specific tools used and the 'mashup' approach. Preliminary findings will be beneficial to others considering using mashups for visualization. The specific techniques developed may be more widely applied to offer insights into the structure of multifarious spatio-temporal data of the type explored here. Index Terms -Large dataset visualization, text and document visualization, multiresolution visualization, geographic visualization, applications of infovis.
doi:10.1109/tvcg.2007.70570 pmid:17968062 fatcat:zraivvtbqngzrlf7tifemsfk74