The overall design of thematic maps refers to the basic outline of maps initially proposed after the tasks and requirements are clear, including the selection of projection, the definition of scale, the delineation of the scope of maps, the planning of maps and the drawing of design sketches.
The overall design of the thematic map is more complex than the normal map and the national basic topographic map. The preparation of a thematic map requires not only the close integration of disciplines and drawings, but also an in-depth understanding and mastery of the use of the frames and the requirements of users. On this basis, the basic outline of the design frame can be made. The specific content to be understood includes:
1) Is the frame dedicated or multi-purpose
Thematic maps can be used both in a dedicated and multi-purpose manner, and are increasingly being developed in multiple directions, and correspondingly produce a variety of patterns for a map.
2) Similar thematic maps published
This paper analyses the advantages and disadvantages of these maps in use, absorbs their strengths and improves their deficiencies, so as to better meet the needs of map users.
3) Identify the special requirements of map users
According to the requirements of different readers, different uses and different occasions of use, the thematic maps compiled are satisfied considering whether they are used for planning, reference, teaching and so on.
After clarifying the use and requirements of the above-mentioned maps, we should clarify the guiding ideology of the overall design, draw up thematic content items, highlight the key points, and put forward the overall design plan of the maps.
The regional scope of thematic map sheets is determined according to their uses and requirements. The appropriateness of scope selection has a great influence on the efficiency of map sheets and is closely related to the mathematical basis of thematic maps. Like ordinary maps, according to the scope of maps, they can be divided into three forms: single map, single map “inner partition” and partition.
This refers to the extent to which a map can be completely covered in thematic area, usually called a cut. The thematic area is placed in the middle of the frame, and its shape determines the horizontal, vertical, and long and wide dimensions of the frame. The relationship between the thematic area and the surrounding area should be handled correctly, for the convenience of reading and use, thematic maps are generally designed with horizontal placement as the main style; some of the thematic regional shapes are long, and the direction of the map is from north to south, so it has to be placed vertically.
This means that more than one sheet of full-open paper is divided into several sheets. “Internal dividing” should be in accordance with paper specifications. Generally, the dividing should not be too fragmentary, and the dividing area is generally the same.
Framing is a form commonly used in topographic maps. The framing map is not limited by the scale, the framing line of the framing map is rectangular framing and latitude and longitude framing according to the size of the area, the framing maps are in principle non-overlapping.
In addition, how to determine the scope outside the thematic area in the map outline should also be clearly defined in the overall design. Methods:
Firstly, highlight the thematic area line, which is expressed in the same way both inside and outside the area, only the boundary of the thematic area is widened, or the color halo is added to show the scope of the thematic area, at the same time, it can be closely linked with the adjacent areas.
Secondly, it only indicates the scope of the thematic area, the gap outside the area, and highlights the content of the topic area, there is no connection between the elements in the area and the area outside the area.
Third, there are differences between inside and outside, that is, color is used in the thematic area, monochrome is used outside the area, and the content is simplified. This is the method commonly used in thematic maps.
Thematic map mathematics includes map projection, scale, coordinate network, map configuration and orientation, framing number and ground control basis, among which map projection and scale are the most important.
Uses and requirements of thematic maps
This is the dominant factor affecting the basic design of mathematics, because the projection and scale are designed according to the purpose and requirements of the frame.
Geographical location, shape and size of the mapping area
This element is an important factor, and the location and shape often affect the choice of projection and scale. In the design, the shape and size of the drawing area should be studied in detail, and several programs should be designed at the same time to choose a reasonable solution.
The breadth and form of the map
The size and form of maps have a certain impact on the basic design of mathematics, which is directly related to the use effect.
In the special map mapping, more isometric projection and isometric projection, what kind of projection is used in the specific design depends on the purpose and requirements of the thematic map.
The design of thematic map scale should consider the use and requirements of the map, make full use of the effective area of paper according to the shape and size of the mapping area, and put the scale value into an integer. In the actual design of map scale work, there are often some special problems, such as: do not frame or break the frame, move the map, oblique placing.
Thematic maps should not only be scientific, but also artistic. Graphic design includes name, scale, legend, illustrations (or drawings), text description and outline decoration, etc.
The title of thematic map requires that the theme of the map be concise and generally placed in the center above the map. The font should be proportionate to the size of the picture, mainly in the form of isoline or art.
There are two ways to express scale: one is to use words (such as one to four million) or numbers (such as 1:4000000); the other is to use graphic scale. There are also two ways to divide the scale interval in a graphic. One is to divide the scale interval by unit length, indicating the actual length represented; the other is to divide the scale interval by the number of kilometers in the field, and each grid is to calculate the length on the graph in proportion. The scale is usually placed below the legend, or below the center of the outer outline or under the name of the upper outline.
Legend symbols are the manifestation of thematic content, the content, size and color of symbols in legends should be consistent with that in the picture, mostly under the picture.
The attached maps refer to the maps added to the main maps. In thematic maps, the main function of the attached maps is to supplement the insufficiency of the main maps. The attached maps in thematic maps include enlarged maps of key areas, supplementary maps of contents, schematic maps of the location of main maps, charts and so on. The location of the drawings should be flexible.
Textual description and statistics of thematic maps require simplicity and conciseness, which are generally arranged in legends or in gaps in maps. Other relevant notes should also be included in the text description.
The overall design of thematic maps must be flexible and specific depending on the shape of the drawing area, the size of the drawing surface, the legend and text description, the appended drawings and the name of the drawing, so as to make the whole drawing vivid and obtain more information. Figures 11-17 show several different styles of graphic design.
Figures 11-17: An example of graphic design