Getting started with googleVis

How this presentation works

This presentation uses the deck.js jQuery frame­work for cre­at­ing HTML pre­sen­ta­tions by Caleb Troughton.

• Use arrow keys to navigate
• Type m to get an overview of the slides
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Introduction to googleVis

• googleVis is a package for R and provides an interface between R and the Google Visualisation API

• The functions of the package allow users to visualise data with the Google Visualisation API without uploading their data to Google

• The output of googleVis functions is html code that contains the data and references to JavaScript functions hosted by Google

• To view the output a browser with Flash and Internet connection is required, the actual chart is rendered in the browser

Motivation

Google Visualisation API

• Google integrated the motion charts into their Visualisation API

• Google Charts Tools provide interactive charts for web pages API uses JavaScript and DataTable / JSON as input
• Output is either HTML5/SVG or Flash
• Browser with internet connection required to display chart
• Please read the Google Visualisation Terms of Use and Google Maps Terms of Use before you start

Motion chart example

• Example (User guide):
• Click the play button to see the dynamics over time

Source code of the motion chart

Key ideas of googleVis

• Create wrapper function in R which generate html files with references to Google's Visualisation API

• Transform R data frames into JSON objects with RJSONIO

• Display the HTML output with the R HTTP help server

History of googleVis

• Development started in August 2010 by Markus Gesmann and Diego de Castillo

• First draft code was written to visualise Lloyd's data

• First public version released on CRAN on 3 December 2010

• We presented googleVis at LondonR and useR! 2011

• Project web site, with examples and case studies:
  http://code.google.com/p/google-motion-charts-with-r/

Version 0.2.11 provides interfaces to:

Motion Charts Annotated Time Lines Maps Geo Maps and Charts Intensity Maps Tables Gauges Tree Maps Line-, Bar-, Column-, Area- and Combo Charts Scatter-, Candlestick-, Pie- and Org Charts

The googleVis concept

Charts: 'gvis' + ChartType For a motion chart we have gvisMotionChart(data, idvar='id', timevar='date', options=list(), chartid) Output of googleVis is a list of list Specific parts can be extracted, e.g. the data or chart This is particular helpful if the package functions are used in solutions where the user wants to feed the visualisation output into other sites

Embedding googleVis chart into your web page

Suppose you have an existing web page and would like to integrate the output of a googleVis function, such as gvisMotionChart.

In this case you only need the chart output from gvisMotionChart. So you can either copy and paste the output from the R console

R> print(M, 'chart') ## or cat(M$html$chart)

R> print(M, 'chart', file='myfilename')

World Bank Example

Setting options

• Options follow the Google Visualisation API documentation and are set in a named list
• See the help page of the individual googleVis function for more details
• Line chart with individual options set

Line chart example

Mapping data with a geo chart

useR!2011 participants by country

Merging gvis-objects

Outlook: Event Listeners

• Google visualisations can fire and receive events. It exposes two Java Script methods:
  • google.visualization.events.trigger() fires an event,
  • google.visualization.events.addListener() listens for events
• The 'addListner' method expects Java Script code, which can be embedded into a gvis-object via options as (undocumented) parameter gvis.listener.jscode

Event listener example

Click on a coloured country and Wikipedia will be launched.

Conclusions

• The Google charting interface is easily accessible to
  • data analysts and
  • non-data analysts
• googleVis enables R-users to
  • create quickly powerful analysis tools,
  • which can be shared online
• However:
  • It is difficult to embed charts in PDF or PowerPoint presentations
  • HTML presentations such as deck.js provide a good alternative

Thank you

• See also:
  • The googleVis package vignette
  • The demos of the package: demo(googleVis)
  • The project site: http://code.google.com/p/google-motion-charts-with-r/
  • My blog: http://lamages.blogspot.com/
• Contact:
  • Please contact us with ideas, suggestions or if you would like to collaborate:
    [email protected]
  • or use our feedback form

Thanks to ...

• Henrik Bengtsson for providing the 'R.rsp: R Server Pages' package and feedback
• Duncan Temple Lang for providing the 'RJSONIO' package
• Sebastian Pérez Saaibi for his inspiring talk on 'Generator Tool for Google Motion Charts' at the R/RMETRICS conference 2010
• All the guys behind www.gapminder.org and Hans Rosling for telling everyone that data is not boring
• Deepayan Sarkar for showing us in the lattice package how to deal with lists of options
• Google, who make the visualisation API available
• Paul Cleary for a bug report on the handling of months: Google date objects expect the months Jan.- Dec. as 0 - 11 and not 1 - 12.

Thanks to ...

• Ben Bolker for comments on plot.gvis and the usage of temporary files
• John Verzani for pointing out how to use the R http help server
• Cornelius Puschmann and Jeffrey Breen for highlighting a dependency issue with RJOSNIO version 0.7-1
• Manoj Ananthapadmanabhan and Anand Ramalingam for providing ideas and code to animate a Google Geo Map
• Rahul Premraj for pointing out a rounding issue with Google Maps
• Mike Silberbauer for an example showing how to shade the areas in annotated time line charts
• Tony Breyal for providing instructions on changing the Flash security settings to display Flash charts locally
• Christopher Gandrud for pointing out deck.js