Labels

Labels are texts associated with cartographic features. They allow information related to these features to be displayed directly on the map. For example, it is possible to display city names from a point layer representing urban centers.

The Labels section, accessible via the labels icon , allows you to configure the content, style, and display of labels for a layer's features.

1	Check this box to display labels in JMap NG applications.
2	Font Click this button to select the label text style: font, font size, bold, italic, font color, outline, and outline color.
3	Text field for writing the label content. See the Label Content section for details.
4	Attributes Attributes available for labels. These are the layer attributes you check in the Properties section.
5	Functions Functions available for labels. The Label Content section details these functions.
6	Zoom levels Zoom level range at which labels are displayed. Specify the range by dragging the indicators on the bar or entering the minimum and maximum zoom values.
7	Position Determine the label position relative to the feature. Click to select from the available positions. Allow overlapping Check this box to allow the layer's labels to overlap each other and overlap labels from other layers. This option may be useful to ensure that all labels in a layer are displayed. Follow line Line features only. Check this box to make the label text follow the shape of curved lines. Spacing (pixels) Line features only. Specify the spacing (in pixels) between repeated labels on the same line.
8	Set the pixel offset on both dimensions of the label position relative to the feature.
9	Frame Check the box to add a frame around the label text. Select the background and border color of the frame.
10	Rotation If you check Rotation by attribute, select the numeric attribute whose values will be used as the rotation angle, and the direction of rotation. Only line features have this option. If you check Follow map rotation, labels will follow the map rotation.
11	Proportional size By default, label text is displayed at the specified font size regardless of the zoom level. Check this option to have the label text size adjusted proportionally to the map's zoom level. Drag the point on the bar to select the reference zoom level at which the text is displayed at the specified font size. When the map zoom level changes, the text size is adjusted accordingly.
12	Click the language of your choice to enter the label content in the selected language.

Label Content

Labeling is done by defining a text that constitutes the label content. This can span multiple lines and contain both:

• Static text (unchanged)

• Dynamic functions (variables), automatically replaced by their value when displayed.

Available functions:

ev(attrib)	Replaced by the value of the corresponding attribute. Example: ev(id) displays the value of the entity's id attribute.
ev(attrib, useValueDomain)	When true is specified for useValueDomain, replaced by the value domain label for the value of attribute attrib. When false (or omitted), replaced by the attribute value itself. Example: ev(categorie, true)
ifNull(attrib, value)	Replaced by value only if the attribute attrib is null. If the attribute value is not null, nothing is displayed. Example: ifNull(temp, N/A) displays N/A if the value of attribute temp is null.
ifNotNull(attrib, value)	Replaced by value only if the attribute attrib is not null. If the attribute value is null, nothing is displayed. Example: ifNotNull(land_value, $) displays $ only if the value of land_value is not null.

To configure label content:

1. Enter the desired static text.

2. To add dynamic content, place the cursor at the desired location in the text field.

3. Click the desired function. It is automatically inserted into the text, and a menu opens to let you choose the attribute to use.

4. Select the attribute and, if necessary, specify a value.

5. Click to save the label content.