The "Attributes" tab in the "label thematic map" window is primarily used to set display parameters for the label objects (text) in the current label thematic map. It should be noted that the "Attributes" tab parameters are the same for uniform label thematic maps, ranges label thematic maps, and custom style label thematic maps.

• Label expression

  Used to specify the thematic variable used by the current label thematic map, which determines the text content displayed on the label objects of the label thematic map. The thematic variable can be a single property field or a mathematical expression of fields.

  • The drop-down list of the combo box lists all property field names of the vector dataset used to create the current label thematic map. The field alias is displayed by default here. You can switch to the field name in the File tab -> Options group. For details, please refer to the Preferences document. You can select any field to change the thematic variable used by the current label thematic map. You can also enter a field name in the combo box, but the field must exist in the combo box's drop-down list. Once a field is confirmed, the current label thematic map uses the new thematic variable to re-label objects in the layer.
  • If you want to use a mathematical expression of property fields as the thematic variable for the label thematic map, you need to select the "expression..." item in the combo box's drop-down list. Then, construct the mathematical expression of property fields in the pop-up "SQL Expression" dialog box. After the field expression is built, the current label thematic map uses the new thematic variable to re-label objects in the layer.
  • If you want to use connectors to display multiple fields, you need to select the "expression..." item in the combo box's drop-down list. Then, construct the expression of property fields in the pop-up "SQL Expression" dialog box. After the field expression is built, the current label thematic map uses the new thematic variable to re-label objects in the layer. For detailed information on field expressions, please refer to Label Thematic Map Label Expression Description.

Notice

• If the field expression uses SQL Expression to concatenate multiple fields for display, and a text-type field involved in the concatenation has a null value, the set thematic map label will be considered invalid and cannot be displayed normally because SQL Expression does not support operations on null values. As shown in the figure below: The two concatenated fields are Name (text-type field) and GDP_2000. Since object 2 has a null value for the Name field, its label is not displayed normally, as shown in Figure 1.
• When labels cannot be displayed normally due to null values in text-type fields as mentioned above, it is recommended that when building the SQL Expression, you first check if the field value is null. If it is null (null), return an empty string; then the label can be displayed normally. For example, in a MySQL database, use the ifnull function for null value checking: ifnull(Name,"") || GDP_2000. If Name is not null, the ifnull function returns Name; otherwise, it returns the result of the "" string. This yields a label thematic map as shown in Figure 2. Different databases have different functions for checking if a field value is null. Please input the correct checking function according to the specific database you are using.

  

• When creating a thematic map for data with Oracle Plus or SQL Plus engine types, the field expression can only be a field value or a field operation expression, such as (SmID) or (SmID + 1). Currently, setting thematic map fields via conditional expressions is not supported. If the set field expression is a conditional expression, such as: "SmID > 100", then creating the thematic map will fail.

• Labels are enumeration information.

This requires that the field selected for the label expression has a range set. The steps for domain settings are as follows:

Right-click the dataset -> Properties, then in the Properties page that pops up on the right -> Range tab, set the domain information for the field.

The comparison of label display effects with or without checking "Labels are enumeration information." is shown in the figure below:

• "Background Settings" Area

Used to add a background of specified shape and style to the label objects (text) in the label thematic map. This background is for the text, different from the background of the characters within the text.

Background Shape: Used to control the background shape of the text. You can add a background to the text by selecting items from the combo box drop-down list. The main forms of background shapes are:

• Default: Text in the label thematic map has no background shape decoration.
• Rectangle, Rounded Rectangle, Ellipse, Diamond, Triangle: Using any of these five shapes will use the corresponding graphic as the background shape for the text in the label thematic map. Simultaneously, the "Settings" button for the background style below becomes available, used to set the background style for the text in the label thematic map.
• Point Symbol: Text in the label thematic map uses a point symbol as the background for the text in the label thematic map.

Background Style: Used to control the style of the text background shape. Click the "Settings" button on the right to set the background style for the text in the label thematic map. When the background shape is Rectangle, Rounded Rectangle, Ellipse, Diamond, or Triangle, the Fill Symbol Style Settings dialog pops up; when the background shape is Point Symbol, the Point Symbol Style Settings (Map and Layout) dialog pops up.

Background Margin: Used to set the distance between the text and the label background border. Simply enter a value in the numeric box; the unit is pixels. Note: The background margin can only be set when the background shape is set to Rectangle or Rounded Rectangle, and the background style is System 0 or System 1.

Background Shadow: After setting the background shape, you can set the color of the background shadow, offset x, and offset y.

• Color: Sets the color of the background shadow. The default is gray (FF7F7F7F).
• Offset X: Sets the horizontal offset of the background shadow.
• Offset Y: Sets the vertical offset of the background shadow.

• Offset Settings Area

  Used to adjust and control the display effects of label objects (text) in the label thematic map.

  • Offset Unit: Used to set the unit for the offset value. Click the drop-down button on the right. In the pop-up drop-down menu, the system provides two offset units for you to choose from: "Unit" and "0.1mm". "0.1mm" indicates the symbol offset is in units of 0.1mm; "Unit" means the set offset is consistent with the unit of the map's coordinate system.
  • Offset X: Used to set the horizontal offset of the label relative to the object it expresses. You can directly enter a numerical value to set the offset; you can also select a numeric field from this layer and use the field value as the offset.
  • Vertical Offset: Used to set the vertical offset of the label symbol relative to the object it expresses. You can directly enter a numerical value to set the offset; you can also select a numeric field from this layer and use the field value as the offset.

Note: Setting the offset by specifying a field is only valid for point label thematic maps.

• Show Leader Line:

  If this checkbox is checked, when a label is offset from the object it annotates, they can be connected by a leader line.

  • Linear Style: Sets the style of the leader line, supporting three types: straight line, common polyline, and right-angled polyline.
  • Line Symbol: Sets the style of the leader line. Click this button to pop up the Styles window where you can set the symbol style of the leader line. For details, please refer to: Line Symbol Style Settings
  • Leader Line Anchor Point: Used to set the starting position of the leader line, i.e., on which side of the object it is located. If the line style is a common polyline, setting a leader line anchor is not supported.It provides nine anchor point setting methods: adaptive, top-center, top-right, center-left, center-center, center-right, bottom-left, bottom-center, bottom-right. If adaptive is selected, the system will automatically calculate and select the anchor point among the eight anchor points (top-center, top-right, center-left, center-center, center-right, bottom-left, bottom-center, bottom-right) that is nearest to the original anchor point of the leader line.
• "Effect Settings" Area

  Used to adjust and control the display effects of label objects (text) in the label thematic map.

  • Flow: If this checkbox is checked, the rendering style of the thematic map can flow display, meaning labels will move as the map changes to achieve the optimization effect of showing all. When the flow effect is enabled, do not use the partly refresh function, otherwise the partly refresh effect may display incorrectly (SuperMap iDesktopX does not support the partly refresh function). Note: The flow function is not supported when creating label thematic maps for point layers.
  • Superscript/Subscript: If this checkbox is checked, superscript and subscript display effects are achieved according to the rules set in the label expression. When using superscript/subscript, please note the following issues:
    • The superscript/subscript function does not currently support parameters like label alongline, rotation angle, new line display, etc.
    • The superscript/subscript function does not currently support label expressions with delimiters.
    • Font effects like strikethrough and underline do not support the superscript/subscript function.

    For more information about superscript/subscript, please see the Superscript/Subscript page.

  • Show Slivers: If this checkbox is checked, it can display labels corresponding to small objects in the label thematic map. Otherwise, depending on the scale, labels for some small objects will be ignored, i.e., the labels for small objects will not be displayed.
  • Landscape Display Tags: If this checkbox is checked, labels can be displayed vertically. Note: If the "label alongline" checkbox is checked or the font's "rotation angle" is set, then setting "landscape display tags" will not take effect.
  • Label Always Top: If this checkbox is checked, labels will be displayed on top. This is mainly applied when layer groups are used. Label layers within a group might be obscured by other normal layers (e.g., polygon layers) located in the upper layer group. To maintain the layer group state while preventing labels from being obscured, you can check this property. If multiple label layers have this property set, the display order among labels will be determined by the layer order.
  • Label Mask: If this checkbox is checked, it can remove the area of line or polygon objects covered by the label, making the label clearer. This is suitable for contour line label thematic maps.
  • No Overlap: If this checkbox is checked, it allows label objects on the map to automatically adjust within a certain range, so that labels are displayed simultaneously without overlapping or interfering with each other.
    • Text Avoid of Two Directions: Allows labels on the map to adjust to several positions around the object they annotate. The alignment relationships for the object are shown in the figure below. For example: If the alignment set for the label thematic map layer is top-left corner alignment, then if overlap occurs, the no overlap function will calculate whether its symmetrical point (top-right corner point) will cause overlap—i.e., whether overlap occurs when the top-right corner point of the label text's bounds aligns with the anchor point of the annotated object. If no overlap occurs, then this alignment is used as the avoidance result.

      

    • Avoid at Four Directions: Allows labels on the map to adjust to the four directions (bottom-left, top-left, bottom-right, top-right) of the bounding rectangle of the annotated object according to a certain order (bottom-left, top-left, bottom-right, top-left), selecting an alignment that will not cause overlap, ultimately allowing labels to be displayed simultaneously without overlapping or interfering with each other.

      

    • Avoid at Eight Directions: Allows labels on the map to adjust to the eight directions (bottom-left, left-center, top-left, top-center, bottom-center, bottom-right, right-center, top-right) of the bounding rectangle of the annotated object according to a certain order (bottom-left, left-center, top-left, top-center, bottom-center, bottom-right, right-center, top-right), selecting an alignment that will not cause overlap, ultimately allowing labels to be displayed simultaneously without overlapping or interfering with each other.

      

    • Avoid Surround Text: Allows labels on the map to adjust to the surrounding directions of the bounding rectangle of the annotated object, selecting a direction for display that will not be overlapped.
  • Numeric Text Precision: Used to set the precision for displaying numeric text on labels. This only takes effect when the content in the label expression is pure numbers. The system provides 9 precision levels from 0.00000001 to 1. The default is no precision. You can select the desired precision from the drop-down menu to the right of the numeric text precision. For example, assuming the precision is 1, then an object with a field value of 178.5 will be displayed as 179 in the label thematic map; if it is the default value (no precision), then each object's field value is directly shown in the thematic map.