Label thematic maps are primarily used to annotate and explain maps. You can use one or more fields from the layer properties to label objects such as points, lines, and polygons. During the mapping process, text or numeric fields are commonly used for labeling, such as place names, road names, river widths, and contour elevation values.

Map annotations help provide descriptive explanations for current map objects, increasing the information capacity of the map. By creating label thematic maps, you can quickly label objects in the map, avoiding the hassle of manually adding annotations. During the creation of label thematic maps, the application automatically generates text labels based on the attributes of one or more fields and places these labels in appropriate positions. Considering that overlapping can easily occur between annotations when multiple layers are superimposed, you can manually adjust the position of individual labels using the "move label" function.

The application can create four types of label thematic maps: uniform, unique value, graduated color, and matrix. Additionally, the program provides templates for these four types of label thematic maps. In the layer manager, select a vector layer, right-click, and choose "create thematic map..." from the context menu. This will pop up the "create thematic map" dialog box, where you can select a type of label map template or create a new thematic map based on default effects.

You can also modify label thematic maps through the label thematic map window. Depending on the type of label thematic map you selected, modify various parameters of the created label thematic map in the corresponding "label thematic map" window to achieve a thematic map effect that better meets your needs.

This chapter will introduce the following content:

• Single Symbol Label Thematic Map: Uses one style to label all objects, commonly used in mapping processes, such as labeling provincial and prefecture-level administrative regions in a national map. Specifically, it supports setting the font type, size, rotation angle, and font color of labels by selecting property fields, enabling custom label settings to meet different label display requirements.
• Unique Value Label Thematic Map: Classifies object labels based on the values of a specified field expression. Labels with the same value are grouped into one class and displayed with the same style, while labels of different classes are displayed with different styles. Here, a unique value corresponds to a sub-item of the unique value label thematic map.
• Graduated Color Label Thematic Map: Must specify a range field. According to the specified range segments, labels within the same range segment are represented with one style, and labels in different range segments are represented with different styles. That is, the label thematic map displays multiple styles based on range segments.
• Matrix Label Thematic Map: Uses a matrix structure to organize label content, capable of integrating symbols, images, and text into a label matrix to label objects in the map. Moreover, a label matrix can be nested within matrix cells. Therefore, matrix label thematic maps are highly suitable for expressing complex thematic map information, such as weather forecast thematic maps and tourism thematic maps.