mages' blog

The Google Charts API is quite powerful and via googleVis you can access it from R. Here is an example that demonstrates how you can zoom into your chart.

Last week I had the honour to give the opening keynote talk at the Talking Data South West
conference, organised by the Exeter Initiative for Statistics and its Applications. The event was chaired by Steve Brooks and brought together over 100 people to discuss all aspects of data: from collection and analysis through to visualisation and communication.

Building interactive relationships with data and colleagues

The programme was very good with a variety of talks such as How data collection from smart phones can improve agronomic decision making in potato crops by Robert Allen or Spatial data and analysis in the improvement of aquatic ecosystem health and drinking water quality by Nick Palling. I also liked Richard Everson's presentation on Visualising and understanding multi-criterion league tables, which showed new ideas to create rankings.

However, my highlight was Alan Smith's talk on Information for the Masses: Using Visualisation to Engage the Public. Alan heads up the Data Visualisation Unit at the Office for National Statistics and they created some fantastic online visualisation tools. He presented some interactive examples of the Census 2011 data set. Alan mentioned the hilarious story of a young lady, who had moved from Leeds to Elmbridge and used the Census data to find out why her new home was so dull compared to her old.

Screen shot of the 2011 Census comparator

The screen shot shows the age distribution of Leeds (left) and Elmbridge (right). Focus on the 20-24 year old age group and you'll get the joke.

Today I feel very lucky, as I have been invited to the Royal Statistical Society conference to give a tutorial on interactive web graphs with R and googleVis.

I prepared my slides with RStudio, knitr, pandoc and slidy, similar to my Cambridge R talk. You can access the RSS slides online here and you find the original R-Markdown file on github. You will notice some HTML code in the file, which I had to use to overcome my knowledge gaps of Markdown or its limitations. However, my output format will always be HTML, so that should be ok. To convert the Rmd-file into a HTML slidy presentation execute the following statements on the command line:

Rscript -e "library(knitr); knit('googleVis_at_RSS_2012.Rmd')"
pandoc -s -S -i -t slidy --mathjax googleVis_at_RSS_2012.md 
  -o googleVis_at_RSS_2012.html

Tonight I will give a talk at the Cambridge R user group about googleVis. Following my good experience with knitr and RStudio to create interactive reports, I thought that I should try to create the slides in the same way as well.

Christopher Gandrud's recent post reminded me of deck.js, a JavaScript library for interactive html slides, which I have used in the past, but as Christopher experienced, it is currently not that straightforward to use with R and knitr.

Thus, I decided to try slidy in combination with knitr and pandoc. And it worked nicely.

I used RStudio again to edit my Rmd-file and knitr to generate the Markdown md-file output. Following this I run pandoc on the command line to convert the md-file into a single slidy html-file:

pandoc -s -S -i -t slidy --mathjax Cambridge_R_googleVis_with_knitr_and_RStudio_May_2012.md -o Cambridge_R_googleVis_with_knitr_and_RStudio_May_2012.html

Et volià, here is the result:

Addition (2 June 2012)

Oh boy, knitr and Markdown are hitting a nail. With slidify by Ramnath Vaidyanathan another project sprung up to ease the creation of web presentations.

Data analysis is often an iterative and interactive process. However, when I present about this subject, I feel often limited by the presentation software I use. It doesn't matter if I use LaTeX/PDF, PowerPoint or Keynote. In all cases it is either very difficult or impossible to include interactive charts, such as Flash or SVG charts. As a result I have to switch between various applications during the talk. This can be fun, but quite often it is not.

The other day I came across a presentation by Christopher Gandrud. Christopher had used deck.js, a JavaScript library for building HTML presentations by Caleb Troughton.

This looked like an interesting approach to me and fortunately the learning curve was not too steep, although I am by no means an html or JavaScript expert. So I created my first deck.js presentation based on the content of previous googleVis presentations. For the first time I can embed videos, Flash and SVG charts without using lots of different apps. I am actually quite pleased by the result, see here: Getting started with googleVis

Now imagine a presentation hosted on a server with R installed! You could combine your slides with R using one of the following packages R.rsp, brew, Rook, etc and run live demos, without opening a console.