Data are values of qualities or quantitative variables belonging to a set of items. Data are results of measurements and can be visualised with graphs or images.
What is data visualisation? Based on the first definition, we can say that it is the visualisation of data. Data itself carries no meaning. For data to become information it has to be interpreted. Data visualisation is one of the steps in analysing data and presenting it to users with the goal to communicate information clearly and efficiently using statistical graphics. It is an essential part of the communication process.
In summation, data visualisation is both an art and a science. There’s a tremendous focus on using the right visualisation type to convey the information we want users/clients to understand.
Image source: http://nathan.com/information-interaction-design-a-unified-field-theory-of-design/
visualising data 