As one of the industry-renowned data visualization experts Edward Tufte once said, “The world is complex, dynamic, multidimensional; the paper is static, flat. How are we to represent the rich visual world of experience and measurement on mere flatland?” There’s indeed just too much information out there to be effectively analyzed by all categories of knowledge workers. More often than not, traditional tabular row-and-column reports do not paint the whole picture or — even worse — can lead an analyst to a wrong conclusion. There are multiple reasons to use data visualization; the three main ones are that one:
Cannot see a pattern without data visualization. Simply seeing numbers on a grid often does not tell the whole story; in the worst case, it can even lead one to a wrong conclusion. This is best demonstrated by Anscombe’s quartet, where four seemingly similar groups of x and y coordinates reveal very different patterns when represented in a graph.
Cannot fit all of the necessary data points onto a single screen. Even with the smallest reasonably readable font, single line spacing, and no grid, one cannot realistically fit more than a few thousand data points using numerical information only. When using advanced data visualization techniques, one can fit tens of thousands data points onto a single screen — a difference of an order of magnitude. In The Visual Display of Quantitative Information, Edward Tufte gives an example of more than 21,000 data points effectively displayed on a US map that fits onto a single screen.