Protovis-GWT 0.4.1 released

Protovis-GWT is an open source GWT data visualization module. The goal of Protovis-GWT is to make the Protovis JavaScript visualization API available in GWT by wrapping the original JavaScript code using JSNI.

Protovis-GWT supports a wide range of visualizations (Area chart, bar chart, pie chart, line chart, stacked charts, treemap, sunburst, icicle diagram, dendrogram, force-directed graph, arc diagram, matrix diagram, box-and-whisker plot, streamgraph, bullet chart, candlestick chart). It implements the complete API of the basic Protovis Mark classes (Mark, Area, Bar, Dot, Label, Line, Wedge) and enables you to create custom visualizations in GWT, similar to the ones you can create with the Protovis library in JavaScript.

In Protovis-GWT 0.4.1, support for the Protovis pan and zoom behaviors was added. The ellipse mark type, which is not part of the original Protovis, was added. Protovis-GWT 0.4.1 is now based on GWT 2.3 (instead of 2.1) and supports Internet Explorer 9.

More information on Protovis-GWT:

• Wiki Page
• Example Visualizations
• Downloads
• Source Code

Protovis-GWT 0.4 Released

Update: A newer version of Protovis-GWT has been released. Please see the wiki page for the latest information on Protovis-GWT.

Protovis-GWT is an open source GWT data visualization module. The goal of Protovis-GWT is to make the Protovis JavaScript visualization API available in GWT by wrapping the original JavaScript code using JSNI.

Protovis-GWT supports a wide range of visualizations (Area chart, bar chart, pie chart, line chart, stacked charts, treemap, sunburst, icicle diagram, dendrogram, force-directed graph, arc diagram, matrix diagram, box-and-whisker plot, streamgraph, bullet chart, candlestick chart). It implements the complete API of the basic Protovis Mark classes (Mark, Area, Bar, Dot, Label, Line, Wedge) and enables you to create custom visualizations in GWT, similar to the ones you can create with the Protovis library in JavaScript.

In Protovis-GWT 0.4, support for network visualizations (Arc diagram, Force-directed graphs, Matrix diagrams) was added. Several classes were moved into the PV class to align the syntax closer to the original Protovis syntax. A stable sort implementation was added to JsArrayGeneric, and various other API improvements were made.

More information on Protovis-GWT:

• Wiki Page
• Example Visualizations
• Downloads
• Source Code

Protovis-GWT 0.3 Released

Update: A newer version of Protovis-GWT has been released. Please see the wiki page for the latest information on Protovis-GWT.

Protovis-GWT is an open source GWT data visualization module. The goal of Protovis-GWT is to make the Protovis JavaScript visualization API available in GWT by wrapping the original JavaScript code using JSNI.

Protovis-GWT 0.3 implements the complete API of the basic Protovis Mark classes (Mark, Area, Bar, Dot, Label, Line, Wedge).

More information on Protovis-GWT:

• Wiki Page
• Example Visualizations
• Downloads
• Source Code

Choosel Visualization Component Architecture

The Choosel framework has been restructured into a more modular architecture that facilitates extensibility and reuse. The new visualization component architecture allows developers to use Choosel visualization components in regular GWT applications, to develop their own Choosel visualization components, and to extend the Choosel visualization workbench. This blog post outlines the architecture, describes its usage scenarios and explains how to update existing Choosel applications.

Visualization Component Architecture Overview (enlarge diagram)

The Choosel visualization component architecture separates the core functionality (which is required to use Choosel visualizations in GWT) from the workbench functionality. The visualizations are extracted into separate visualization modules. The architecture consists of three main components:

• Core module: The choosel.core module contains the core functionality that is required by Choosel visualizations. This includes the resource (i.e. data) framework, the management of visualization states (e.g. data, highlighting, selection), the visualization component API, and also more general services such as logging (which wraps gwt-log). The choosel.core module needs to be inherited by any GWT module that uses Choosel, whether it is a visualization component, a GWT application or a Choosel workbench.
• Visualization modules: Visualization modules provide one or more visualization components that implement the Choosel visualization component API. They can wrap around other libraries, e.g. GWT modules, JavaScript visualization toolkits, or Flash widgets. Choosel provides several visualization modules (map, timeline, text, chart, and graph) that can be used right away.
• Workbench module: The choosel.workbench module provides the persistence and sharing facilities as well as the visualization workspace.

This separation of concerns makes reusing and extending Choosel easier. It enables three ways to leverage Choosel in your own projects:

• Developing your own visualization components: You can implement visualization components that adher to the Choosel visualization component API. These visualization components can then be used by yourself and others to take advantage of Choosel features such as view synchronization, selections, highlighting, and details on demand.
• Using Choosel visualization components in your GWT application: You can use one or several Choosel visualization components as widgets in your GWT application to visualize your data.
• Creating a Choosel-based workbench: You can extend the whole Choosel framework to develop your own visualization workbench, for example for a specific application domain.

Please note that while the modularization itself is complete, the visualization component API is still under development. We plan to release a first stable version in the next few months.

To set up a new Choosel project, please take a look at the development setup. If you are already working on a Choosel-based application, you can update it to use the modular Choosel architecture:

• Check out the different Choosel modules (see development setup)
• Change the dependencies of your Eclipse project (Right click on project --> Properties --> Java Build Path --> Projects) to reference the new Choosel modules, but not the old one (choosel)
• Organize the imports of your .java files (Right click on source folder --> Source --> Organize Imports; then for each class that has problems in the Java editor)
• Fix the static imports (if there are unresolved constants or methods: compare with previous version, insert old static imports and change choosel.client to choosel.core.client)
• Add the visualization configuration file (see ChooselExampleWorkbenchViewContentDisplaysConfigurationProvider for an example)
• Update the client module (see ChooselExampleClientModule for an example)
• Change the .gwt.xml file of your project (see choosel.example.workbench for an example module file)
• Update the servlet references in the web.xml (change choosel.server to choosel.workbench.server)
• Remove old launch config, copy launch config from choosel.example.workbench and adjust it to your project.

You should be able to run your modular Choosel application now. If there are still problems, feel free to complain on the Choosel mailing list :-)

Protovis-GWT 0.2 Released

Update: A newer version of Protovis-GWT has been released. Please see the wiki page for the latest information on Protovis-GWT.

Protovis-GWT is an open source GWT data visualization module. The goal of Protovis-GWT is to make the Protovis JavaScript visualization API available in GWT by wrapping the original JavaScript code using JSNI.

Protovis-GWT 0.2 has an improved event handler interface and now supports the hierarchical visualization examples (dendrograms, sunbursts, icicles, indented trees, circle packing, node-link trees, and treemaps) and the bubble chart example from the Protovis example library.

More information on Protovis-GWT:

• Wiki Page
• Example Visualizations
• Downloads
• Source Code

Protovis-GWT 0.1 Released

Update: A newer version of Protovis-GWT has been released. Please see the wiki page for the latest information on Protovis-GWT.

Protovis-GWT is an open source GWT data visualization module. It wraps the Protovis JavaScript visualization API for usage in GWT. Protovis-GWT 0.1 (Download Module) is an early development version based on Protovis 3.2 and GWT 2.1. Several examples from the Protovis example gallery have been re-implemented using Protovis/GWT. Protovis-GWT is developed as part of the Choosel Visual Data Exploration Framework.

Version 0.1 implements the Protovis functionality for most conventional and custom examples from the Protovis website. The support for tree, graph and map visualizations as well as for interaction is still limited. Protovis-GWT currently supports Chrome, Firefox and Safari. IE is not yet supported.

Getting started with Protovis-GWT in your GWT project is easy:

1. Download the Protovis-GWT module jar file
2. Add the jar file to the build path of your GWT project
3. Inherit org.thechiselgroup.choosel.protovis.ProtovisGWT by adding <inherits name='org.thechiselgroup.choosel.protovis.ProtovisGWT'/> to your GWT module XML definition (.gwt.xml).
4. Use the Protovis Widget in your code, e.g.

public void onModuleLoad() {
  RootPanel.get().add(new ProtovisWidget() {
    protected void onAttach() {
      super.onAttach();
      initPVPanel();
      // create visualization here...
      getPVPanel().render();
    }
  });
}

More information on Protovis-GWT:

• Wiki Page
• Example Visualizations
• Source Code

Slides of InfoVis 2010 presentation "How Information Visualization Novices Construct Visualizations"

I presented the paper "How Information Visualization Novices Construct Visualizations" at IEEE InfoVis 2010 in Salt Lake City. Here are my slides:

Choosel at VisWeek 2010 and at CASCON 2010

Interested in data visualization on the web? There are several Choosel-related events at VisWeek 2010, CSER and CASCON 2010. Choosel is an open-source framework for browser-based data visualization.

Watch video in full screen and HD for better quality

Oct 24-28, I will present the InfoVis poster "Choosel – Web-based Visualization Construction and Coordination for Information Visualization Novices" at VisWeek 2010. Here is a preview:

Oct 31st, there will be a presentation on Choosel and the Work Item Explorer at CSER. The Work Item Explorer (developed by Patrick Gorman, Del Myers and Christoph Treude) is a research prototype built on Choosel that facilitates the flexible, iterative exploration of Jazz data, focusing primarily on work items.

Nov 1-4, there will be CASCON exhibits on Choosel and the Work Item Explorer. The Choosel exhibit (Bradley Blashko, Lars Grammel) will be at booth X2 near the Central Tower, and the Work Item Explorer exhibit (Patrick Gorman, Christoph Treude) will be at booth U5. The exhibits are open 5pm to 7pm on Monday (Nov 1), from 8.30am to 7pm on Tuesday and Wednesday (Nov 2 and 3), and from 8.30am to 1pm on Thursday (Nov 4).

Choosel Poster at InfoVis 2010

I will present a poster on the Choosel Framework at IEEE InfoVis 2010. The main goal of the Choosel project is to enable software developers and researchers to easily create web-based visual data exploration environments for novices. The poster paper briefly summarizes some of the related work, the features of Choosel, and the results of a prelimary usability evaluation:

Since information visualization has become increasingly vital to experts, it is now important to enable information visualization novices to consume, construct, and coordinate visualizations as well. Choosel is a web-based environment that aims at facilitating flexible visual data exploration for information visualization novices. It supports the iterative construction of multiple coordinated views during the visual data analysis process. A preliminary user study with 8 participants indicated that multiple windows, enhanced drag and drop interaction, and highlighting of items and sets, in particular, support novices in the visual data exploration process in a useful and intuitive way.

Download Poster Abstract (2 pages)

Why Choosel is based on GWT

I presented Choosel to the Visual Interaction Design (VisID) research group at the University of Victoria. Choosel is an open-source framework for web-based information exploration environments aiming at information visualization novices.

The first part of my presentation focused on several design decision behind Choosel. The framework is targeting information visualization novices - those who are not familiar with information visualization and visual data analysis beyond the graphics encountered in everyday life. Two major design decision we made based on those constraints is choosing the web as the target platform and developing Choosel using GWT.

We assumed that those information visualization novices are more likely to look at smaller data sets (up to 5000 items), but are not willing to spent much time getting started with visual data analysis. This was the main driver behind the decision to develop a web-based environment, because this spares user the burden of installing software. We considered removing this entry barrier more important then scalability beyond several thousand data items. As our main goal was to a provide interactive information exploration environment, responsiveness was important and we decided to use primarily technology that runs on the user's computer and not on the server.

In Choosel, we leverage third party visualization components and toolkits such as the Simile Timeline, Protovis and FlexViz. In order to be able to integrate different technologies such as Flash and JavaScript in the browser, we decided to use a JavaScript based technologies. First, we developed a initial prototype using the dojo toolkit. However, it turned out that because of our software development skills and tool support for unit testing, refactoring, and debugging, we were able to develop the same prototype using GWT in about a quarter of the time. The current version of Choosel is based on GWT.

Here are the slides from my presentation:

How Information Visualization Novices Construct Visualizations

Visualization for the masses is a topic that has gained a lot of attraction in the InfoVis community in recent years, e.g. in projects such as IBM ManyEyes. The goal is to enable a wide user population to leverage information visualization technology to understand large amounts of data. This could potentially help them make more informed decisions, and is especially promising as more and more data becomes available (see open data). However, there are still many challenges that need to be addressed so that visualization for the masses can become a reality, ranging from limited visual literacy to insufficient tool support.

Together with Melanie Tory and Margaret-Anne Storey, I investigated how information visualization novices construct visualizations in a laboratory setting. Our research paper "How Information Visualization Novices Construct Visualizations" was accepted for presentation at IEEE InfoVis 2010.

Here is the abstract of our paper:

It remains challenging for information visualization novices to rapidly construct visualizations during exploratory data analysis. We conducted an exploratory laboratory study in which information visualization novices explored fictitious sales data by communicating visualization specifications to a human mediator, who rapidly constructed the visualizations using commercial visualization software.

We found that three activities were central to the iterative visualization construction process: data attribute selection, visual template selection, and visual mapping specification. The major barriers faced by the participants were translating questions into data attributes, designing visual mappings, and interpreting the visualizations. Partial specification was common, and the participants used simple heuristics and preferred visualizations they were already familiar with, such as bar, line and pie charts.

From our observations, we derived abstract models that describe barriers in the data exploration process and uncovered how information visualization novices think about visualization specifications. Our findings support the need for tools that suggest potential visualizations and support iterative refinement, that provide explanations and help with learning, and that are tightly integrated into tool support for the overall visual analytics process.

Download Technical Report

Supporting End Users in Coordinating Multiple Visualizations

As part of my PhD research, I am looking at ways to make visual data analysis more accessible to end users without data analysis expertise. Specifically, I am researching how they can easily coordinate multiple visualizations. This has led to the development of web-based visual analytics research prototype, which I evaluated in a user study. The results indicate that novel concepts such as drop target highlighting, drop previews and using multiple user defined sets are useful and easily usable for end users.

I presented the tool and the results (see poster and presentation below) at the IBM University Days 2010. A version of the visual analytics environment that is tailored to exploring biomedical ontologies is available at: bio-mixer.appspot.com

Poster "Web-based Analytics with Multiple Coordinated Visualizations"

Presentation "A web-based environment for visual client side mashups"

View more presentations from Lars Grammel.