What Is a Thematic Map?

Thematic maps, also known as special maps, are based on the requirements of the map's theme on the geographic base map, highlighting and perfecting one or more elements related to the theme, making the map content thematic and different forms 2. Use-specific maps. ^[1]

Thematic map refers to a map that highlights one or more natural or socio-economic (humanistic) elements in the mapping area as prominently and as completely as possible. The cartographic field of thematic maps is wide, and all information data with spatial attributes can be represented by it. Its contents and forms are various and can be widely used in industries such as national economic construction, teaching and scientific research, and national defense construction. Thematic maps and

Themed

Ordinary maps emphasize the general characteristics of expressing cartographic elements, while thematic maps emphasize the important characteristics of expressing thematic elements, and are as complete and detailed as possible.

Any thematic map is basically composed of thematic elements and basemap elements. The more complex thematic maps are composed of more than two levels, that is, the most important thematic elements are on the first level plane, and the minor thematic elements. On the second level, the more minor theme elements are on the third level, and so on.

The spatial distribution characteristics of the thematic elements

There are three characteristics of the spatial distribution of the thematic elements: first, they are distributed in points or occupy a small area in the field, such as mining points, towns, etc .; second, they are distributed in bands, such as

Representation of point-like elements: fixed-point notation

Point-like elements are often referred to as fixed-point notation, referred to as notation. It uses a variety of symbols of different shapes, sizes, colors, and structures to represent the spatial distribution of the thematic elements and their quantitative and qualitative characteristics. Usually the position of the symbol indicates the spatial distribution of the thematic elements, the shape and color indicate the difference in quality, the size indicates the difference in quantity, the structural symbol indicates the internal composition, and the positioning extension symbol indicates the development trend.

Representation of linear elements: linear notation

Linear or band-shaped distribution elements. Color and graphics are usually used to indicate the quality characteristics of linear elements, such as using color to distinguish different elements.

Modern thematic maps are often used in combination with more than two representation methods to improve the effect of surface expression and transmission.

The thematic element representation method is the basic method for graphic representation of cartographic objects, the essential scientific processing skills for cartographic objects, and the concrete embodiment of the method of graphic thinking in the field of thematic maps. Thematic element representation methods usually require the spatial geographic distribution characteristics, quantity, qualitative characteristics, spatial structure characteristics, and spatial-temporal evolution characteristics of cartographic objects to be displayed visually. The spatial geographic distribution characteristics are the most basic content.

The thematic element representation method is based on the map language to complete the specific graphic expression of cartographic objects, and the visual variables of the map symbols are used to display the characteristics of the thematic elements.