Data visualization is the presentation of data in a graphical format. It reduces the “noise” of data by presenting it visually, making it easier for decision makers to see and understand trends, outliers, and patterns in data.
Maps and charts were among the earliest forms of data visualization. One of the most well-known early examples of data visualization was a flow map created by French civil engineer Charles Joseph Minard in 1869 to help understand what Napoleon’s troops suffered in the disastrous Russian campaign of 1812. The map used two dimensions to depict the number of troops, distance, temperature, latitude and longitude, direction of travel, and location relative to specific dates.