New unique value thematic map

Instructions for use

Creating a unique value thematic map provides two methods: one is creating based on fields in thematic map templates, and the other is creating a thematic map with blank fields. The provided templates include six types: Default, Four-color, Blank, Land Use Type, Boundary Line, and Administrative Division Type. Creating a unique value thematic map based on thematic map templates is not only convenient and fast but also facilitates batch mapping requirements, enabling the reuse of thematic templates. A blank thematic map refers to creating a thematic map without a specific field, where you can specify the field expression yourself.

When using a template, it is necessary to ensure that the field expression for the thematic map exists. If the thematic map field in the template does not exist in the current layer, a dialog box will pop up with the message: "The thematic map cannot display properly because the expression does not exist. Please specify the expression." After re-specifying the field, you can use the template to create the thematic map.

Function entrances

  • Layer Manager->Layer context menu->Create Thematic Map->Unique value thematic map.
  • Thematic Map tab->Unique Values group->Unique Values button.

Operation steps

  1. In the Layer Manager, select a vector layer to create a unique value thematic map.
  2. Right-click and select Create Thematic Map ... from the context menu, or in the Thematic Map tab, Unique Values group, choose a unique value thematic map template to create a unique value thematic map.
  3. A unique value thematic map created based on a template style will automatically be added to the current map window as a thematic layer and will also be added to the Layer Manager accordingly.
  4. Both system-built thematic map templates and user-definable thematic map templates appear under the "Templates" drop-down menu. They can be managed uniformly through the Template Manager. For details, see: "Managing thematic map templates".
  5. In the Thematic Map tab, Unique Values group, click the Unique Values drop-down button and select Blank to create a unique value thematic map with blank fields based on the selected layer. At this time, the expression field for the unique value thematic map is empty. After setting the expression field, the unique value thematic map can be generated based on the field values. Blank thematic maps are suitable for large amounts of data, avoiding the issue of manually modifying fields that do not meet requirements after initialization.
Notes:
  • After selecting a template to create a unique value thematic map, the "Unique value thematic map" window will pop up. This window displays the default settings of the current thematic map, such as the colors of the unique value thematic map and the list of all thematic values. Users can reset the styles of thematic values based on this, obtaining a thematic map effect that better meets their needs by partially modifying the default generated unique value thematic map.
  • After closing the "Unique value thematic map" window, you can double-click the layer in the "Layer Manager" or right-click and select "Modify thematic map" to open the "Unique value thematic map" window for parameter modification and settings.
  • If there are overlapping (intersecting or coinciding) relationships between objects in the dataset, generating a four-color thematic map will fail. If the dataset contains complex polygons (polygons with sub-objects), errors may occur when generating a four-color thematic map.
  • When using the "Four-color map" template to create a thematic map, it first attempts four-color filling. If the four-color filling calculation fails, it will automatically switch to five-color filling.

Related topics

Modifying unique value thematic map