In short, visualization is a visual representation of data, and it is the general name of interactive technology. It presents data in a graphical way, which is convenient for users to observe and understand, and helps users to explore and discover hidden patterns in data, so as to gain understanding and insight into a large number of data.
As the saying goes, a picture is worth a thousand words, that is, some things are very complicated and unrealistic to express in words, but it is very easy to grasp and understand by using graphics.
Taking map navigation as an example, the road, text and geographical information between Hangzhou Wulin Square and West Lake Music Fountain are as follows:
We can see the whole route at a glance on the map. By clicking on the key transition point, you can get the next thread information. This example shows visualization intuitively.
In the era of big data, data sources are diverse and the data scale is huge. Visualization technology can help us observe, understand, explore and discover data.
The general process of visualization is shown in the following figure 1-3:
At present, the field of visualization includes three main branches, namely scientific visualization, information visualization and visual analysis.
The top academic conference in the field of visualization is IEEE VIS, which contains three chapters, just corresponding to the three branches of data visualization.
In the field of data visualization, scientific visualization is one of the most mature research branches, which mainly faces the modeling, operation and processing of data generated by natural science experiments, exploration activities (such as astronomical observation) and computer simulation. Scientific visualization is aimed at specific fields, such as astronomical observation, earthquake research, medical research, nuclear physics research, oil exploration and so on. Its data type is relatively simple, data generally contains physical and geometric structure data, and the task of visualization is generally fixed.
The main differences between scientific visualization and information visualization are as follows:
The purpose of visualization is to display complex data effectively, and the first principle is accuracy and clarity.
Accuracy means that the visualization results reflect the true color or essence of the data;
Clarity means that the meaning expressed by visual effects should be clear.
The outspoken graph, also known as the frequency histogram, is a graph used to represent the frequency distribution in statistics. In a rectangular coordinate system, the abscissa represents the value of a random variable, and the abscissa is generally divided into a series of cells, and each cell corresponds to a group as the bottom of a small rectangle. The ordinate represents the frequency, and the height of each group of small rectangles represents the frequency at which the random variable value falls into the interval. A series of small rectangles form a frequency histogram.