This article describes an algorithm for laying out a list of items diagonally in a square, or nearly square, matrix. The algorithm provides a method for compactly arranging sorted items using proximity and has been used to visualize document similarity data. A Java implementation of the algorithm is presented.
This article describes the Document Visualizer, a prototype document visualization tool that supports the relevance evaluation of information retrieval results by presenting search terms and document similarities in four visual styles: bar charts, matrix charts, a scatter plot, and a document map. Users are able to explore the documents with dynamic queries and interactive sorting.
This article describes a double-ended bar chart that compactly visualizes two numeric values in a single table cell. Visualizing a column of values with double-ended bar charts makes it easy to see trends and outliers in the data.
This article describes the Expanding Table, a tabular user interface component that enables table cells to expand and contract with smooth animation. The Expanding Table can be used for visualization and browsing applications, and when the user interface component for editing table cell values would make tables prohibitively large. An Expanding Calendar is provided as an example application.
This article describes an algorithm for labelling features in interactive applications such as data visualization. In the first phase, a genetic algorithm searches for a set of label positions that minimizes the number of labels that overlap features, other labels, or the bounding box of the region to be labelled. The genetic search has a time limit to ensure that interactive software that uses the algorithm is responsive. If there are any overlapping pixels after the genetic search, the second phase of the algorithm makes small adjustments to the position of the overlapping labels to remove the overlaps.
When visualizing geocoded data points on a map it's common to plot each location with a marker. When many data points are located in the same geographical area, the markers drawn later will overlay the markers drawn earlier. When the markers are opaque, it's difficult to tell at a glance how many data points are located in each region. This article explains how to use transparency to visualize information density.
Partition labels provide a user interface for displaying and interacting with groups of partitioned data. Partition labels enable users to select the items in a partition, transfer the selected items in a drag and drop operation, and change the colour of the partition.
This article describes the Space Filler Explorer, an application for navigating around hierarchical filing systems with three co-ordinated views: a directory tree structure, a list of files, and a 2D tree-map space-filling visualization of the files. Users can dynamically query the tree-map visualization to filter out files based on their size using several relational operators.
Document maps are a new visualization tool that help users filter information retrieval search results. Documents are compactly represented by a square matrix that presents document similarity and frequently occurring search items. Evaluation has shown that document maps enable users to filter search results quickly and accurately.
This article reviews the problems with current visualization software and develops four groups of requirements for visualization software: hardware and software requirements, user requirements, visualization researcher requirements, and visualization developer requirements. I believe that meeting these requirements will produce visualization software that will be effective, flexible, highly usable, and fast and easy to implement.