The label thematic map is mainly used to add annotation descriptions to a map. You can use one or more fields from the layer properties to label objects such as points, lines, and areas. During the mapping process, text or numeric fields are commonly used, such as place names, road names, river widths, and contour elevation values, for labeling.

Map annotations help provide descriptive explanations for the current map object and increase the amount of information carried by the map. By creating a label thematic map, you can quickly label objects in the map, avoiding the trouble of manually adding annotations. During the process of creating a label thematic map, the application automatically generates text labels based on the attribute values of one or more fields and places these labels in appropriate positions. Considering that when multiple layers are overlaid, annotations may easily overlap, 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, and matrix. The program also provides four templates for label thematic maps. In the Layer Manager, select a vector layer, right-click, and choose "Create Thematic Map..." from the context menu. In the "Create Thematic Map" dialog box, you can select a certain type of label map template or create a new thematic map based on the default effect.

You can also modify a label thematic map through the Label Thematic Map window. Depending on the type of label thematic map you select, you can 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.

When creating a label thematic map for island-hole area data and label positions are misplaced, please troubleshoot and handle the issue using the following methods:

• Turn off the Flow function.
• Ensure that the sub-object point order of the data is suitable for labeling, meaning that polygon holes should be counterclockwise. If not, use the Geometry Repair operator tool for preprocessing.
• If it is a compound object, use Protective Decomposition to decompose it into simple objects before labeling.

This chapter will introduce the following content:

• Single Symbol Label Thematic Map: Uses one style to label all objects, which is commonly used in map production, such as labeling provincial and prefecture-level administrative regions on a national map. In particular, it supports setting the font type, size, rotation angle, and font color of labels by selecting a property field, 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, one unique value corresponds to one unique value label thematic map sub-item.
• Graduated Color Label Thematic Map: A graduated field must be specified. According to the specified graduated ranges, labels within the same range are represented with one style, while labels in different ranges are represented with different styles. That is, the label thematic map is displayed with multiple styles based on the graduated ranges.
• Matrix Label Thematic Map: Uses a matrix structure to organize label content, allowing symbols, pictures, and text to be combined into one label matrix for labeling objects in the map. Moreover, a label matrix can be nested within a matrix cell. Therefore, the matrix label thematic map is very suitable for expressing complex thematic map information, such as weather forecast thematic maps and tourism thematic maps.