Tag Archives: grammar of graphics

Brunel: Open Source Visualization Language

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BRUNEL is a high-level language that describes visualizations in terms of composable actions. It drives a visualization engine (d3) that performs the actual rendering and interactivity. It provides a language that is as simple as possible to describe a wide variety of potential charts, and to allow them to be used in Java, Javascript, python and R systems that want to deliver web-based interactive visualizations.

At the end of the article are a list of resources, but first, some examples. The dataset I am using for these is a set of data taken from BoardGameGeek which I processed to create a data set describing the top 2000 games listed as of Spring 2015. Each chart below is a fully interactive visualization running in its own frame. I’ve added the brunel description for each chart below each image as a caption, so you can go to the Builder anytime and copy the command into the edit box to try out new things.

data('sample:BGG Top 2000 Games.csv') bubble color(rating) size(voters) sort(rating) label(title) tooltip(title, #all) legends(none) style('* {font-size: 7pt}') top(rating:100)

This shows the top 100 games, with a tooltip view for details on the games. They are packed together in a layout where the location has no strong meaning
— the goal is to show as much data in as small a space as possible!
In the builder, you can change the number in top(rating:100) to show the top 1000, 2000 … or show the bottom 100. You could also add x(numplayers) to divide up the groups by recommended number of players

data('sample:BGG Top 2000 Games.csv') line x(published) y(categories) color(categories) size(voters:200) opacity(#selection) sort(categories) top(published:1900) sum(voters) legends(none) | data('sample:BGG Top 2000 Games.csv') bar y(voters) stack polar color(playerage) label(playerage) sum(voters) legends(none) at(15, 60, 40, 90) interaction(select:mouseover)

This example shows some live interactive features; hover over the pie chart to update the main chart. The main chart shows the number of people voting for games in different categories over time, and the pie chart shows the recommended minimum age to enjoy a game. So when you hover over ‘6’, for example, you can see that there have been no good sci-fi games for younger players in the last 10 years. Use the mouse to pan and zoom the chart (drag to pan, double-click to zoom).

data('sample:BGG Top 2000 Games.csv') treemap x(designer, mechanics) color(rating) size(#count) label(published) tooltip(#all, title) mean(rating) min(published) list(title:50) legends(none)

Head to the Builder Site to modify this. You could try:

  • change the list of fields in x(…) — reorder then or use fields like ‘numplayers’, ‘language’
  • remove the ‘legends(none)’ command to show a legend
  • change size to ‘voters’ — and add a ‘sum(voters)’ command to show the total number of voters rather than just counts for each treemap tile

Do you want to know more?

Follow links below; gallery and cookbook examples will take you to the Brunel Builder Site where you can create your own visualizations and grab some Javascript code to embed them in your web pages … which is exactly how I built the above examples!

From the Vaults: How to Speak Visualization

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In English, we use many different words to describe the same basic objects. In one survey, researchers Dieth and Orton explored which words were used for the place where a farmer might keep his cow, depending on where the speaker resided in England. The results include words like byreshipponmistallcow-stablecow-housecow-shedneat-house or beast-house. We see the same situation in visualization, where a two-dimensional chart with data displayed as a collection of points, using one variable for the horizontal axis and one for the vertical, is variously called ascatterplot, a scatter diagram, a scatter graph, a 2D dotplot or even a star field.

There have been a number of attempts to form taxonomies, or categorizations, of visualizations. Most software packages for creating graphics, such as Microsoft Excel focus on the type of graphical element used to display the data and then sub-classify from that. This has one immediate problem in that plots with multiple elements are hard to classify (should we classify a chart with a bars and points as a bar chart, with point additions, or instead classify it as a point char, with bars added?). Other authors have started with the dimensionality of the data (one-dimensional, two-dimensional, etc.) and used that as a basic classification criterion, but that has similar problems.

Visualizations are too numerous, too diverse and too exciting to fit well into a taxonomy that divides and subdivides. In contrast to the evolution of animals and plants, which did occur essentially in a tree-like manner, with branches splitting and sub-splitting, information visualization techniques have been invented more by a compositional approach. We take a polar coordinate system, combine it with bars, and achieve a Rose diagram. We put a network in 3D. We addtexture, shape and size mappings to all the above. We split it into panels. This is why a traditional taxonomy of information visualization is doomed to be unsatisfying. It is based on a false analogy with biology and denies the basic process by which visualizations have been created: composition.

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