**Warning heavy tech content**
With the launch of the D-viz toolkit, its come time to describe a little of what happening under the hood (and to an extent why).
Flowchart of the visualisation process in look.iriss.org.uk
First, a note (or two) about our intended audience.
One early decision was to use SVG as our chosen base format, which has some advantages as a resolution independent format (it also allows use the ability to have interactive visualisations in the future), though it is not supported in IE until the latest version (and we’ve received some indications that its support is not complete )
Data has been split into 2 types words and numbers.
Words are simply copied and pasted into a text box, he hope to allow the upload of MS word documents at some point in the future.
‘Numbers’ can be uploaded as excel spreadsheets. This is done using the excellent drupal sheetnode module, which handles both the upload of several formats of spreadsheet, but also displays them in a familiar interface for users.
The dashboard is our term for the form which allows you to choose your options. visualisation options are presented depending on the type of data you uploaded, once chosen you are given supplementary options depending on your chosen visualisation type.
Visualisation (aka the fun part).
To build the visualisations we built 3 different (for lack of a better word) ‘engines’. I’ll describe the protovis engine in depth later, but here are the other two described in brief.
wordclouds, The data is parsed and sent off to a remote server, which generates the svg and returns it.
ISOTYPES, this module generates an svg based on preloaded svg paths for icons, changing size, colour and the number of items based on the data provided.
flowchart for the protovis engine
Once drupal has an SVG file through this process it creates a visualisation content type, and saves the SVG to it. the SVG is also rasterised and a standard image (firstly so it is in a familiar format, secondly to ensure all users can view it). and it is also saved as a .pdf.
While a rather brief explanation of the whole process I hope it gives an insight to the architecture of the site, and the many complexities that can be encountered, and overcome in building a project such as this.