2. Identify data

At the heart of dataviz lies the data; a rich datavisualization will above all be made up of reliable and relevant data to meet the need.

There are therefore two essential points to bear in mind when identifying and selecting the batches of data to be exploited:

• The data must be faithful to what they describe, i.e. they must have been collected honestly and without bias (or if there is bias, with a homogeneous bias between all the data).

• The data must be error-free (or at least contain as few errors as possible).

The next step is to identify the data that can be used. Here again, the analyst must use his or her imagination. In fact, dataviz makes it possible to imagine the superimposition or cohabitation of heterogeneous data (the V stands for variety)....