"Semiology of Graphics" focuses on the theory of information design, particularly in the context of diagrams, networks, and maps. It explores how visual elements can be used to effectively represent and communicate information[2].

The book discusses several visual variables that can be manipulated to represent data, including position, size, shape, value (lightness), color hue, texture, and orientation. These variables form the basis for creating effective visual representations of information.

Retinal variables are visual properties that can be perceived regardless of position, such as size, shape, value, color, texture, and orientation. They differ from planar variables (like position on a 2D plane) in that they can be used to encode additional dimensions of data beyond the two spatial dimensions.

Bertin classifies data into three types: qualitative (nominal), ordered (ordinal), and quantitative. He suggests that different visual variables are more or less suitable for representing each type of data. For example, position and size are effective for quantitative data, while color hue is better suited for qualitative data.

Efficiency in graphic representation refers to the ability of a visualization to convey information quickly and accurately. An efficient graphic allows the viewer to extract the maximum amount of information with the least cognitive effort.

Bertin's image theory suggests that the effectiveness of a graphic depends on its ability to be perceived as a single image or "figuration." This theory emphasizes the importance of creating visualizations that can be quickly grasped as a whole, rather than requiring the viewer to process individual elements separately.

Bertin describes three levels of organization in graphic representation:

1. Elementary level: individual data points or marks
2. Intermediate level: groups or categories of data
3. Overall level: the entire graphic as a single image

Monosemic signs have a single, unambiguous meaning within the context of the graphic. They are preferred in information design because they reduce ambiguity. Polysemic signs, on the other hand, can have multiple interpretations and are generally less effective for clear communication of data.

The principle of graphical economy states that the most effective graphic is one that conveys the desired information with the minimum number of visual elements. This principle encourages simplicity and clarity in design, avoiding unnecessary complexity or decorative elements that do not contribute to the information being communicated.

Bertin's work has had a significant impact on the field of information design and data visualization. His systematic approach to visual variables and data representation has informed modern practices in creating effective charts, maps, and infographics. Many of his principles are still applied in digital visualization tools and techniques used today[2][5].