LABEL

ALIGN [left|center|right]

Since version 5.4 . Specifies text alignment for multiline labels (see WRAP) Note that the alignment algorithm is far from precise, so don’t expect fabulous results (especially for right alignment) if you’re not using a fixed width font.

ANGLE [double|auto|follow|attribute]

• Angle, given in degrees, to draw the label.

• AUTO allows MapServer to compute the angle. Valid for LINE layers only.

• FOLLOW was introduced in version 4.10 and tells MapServer to compute a curved label for appropriate linear features (see MS RFC 11: Support for Curved Labels for specifics).

• [Attribute] was introduced in version 5.0, to specify the item name in the attribute table to use for angle values. The hard brackets [] are required. For example, if your shapefile’s DBF has a field named “MYANGLE” that holds angle values for each record, your LABEL object might contain:

  LABEL
    COLOR  150 150 150
    OUTLINECOLOR 255 255 255
    FONT sans
    TYPE truetype
    SIZE 6
    ANGLE [MYANGLE]
    POSITION AUTO
    PARTIALS FALSE
  END
  

  The associated RFC document for this feature is MS RFC 19: Style & Label attribute binding.

ANTIALIAS [true|false]

Should text be antialiased? Note that this requires more available colors, decreases drawing performance, and results in slightly larger output images.

BACKGROUNDCOLOR [r] [g] [b]

Color to draw a background rectangle (i.e. billboard). Off by default.

BACKGROUNDSHADOWCOLOR [r] [g] [b]

Color to draw a background rectangle (i.e. billboard) shadow. Off by default.

BACKGROUNDSHADOWSIZE [x][y]

How far should the background rectangle be offset? Default is 1.

BUFFER [integer]

Padding, in pixels, around labels. Useful for maintaining spacing around text to enhance readability. Available only for cached labels. Default is 0.

COLOR [r] [g] [b] | [attribute]

• Color to draw text with.

• [Attribute] was introduced in version 5.0, to specify the item name in the attribute table to use for color values. The hard brackets [] are required. For example, if your shapefile’s DBF has a field named “MYCOLOR” that holds color values for each record, your LABEL object might contain:

  LABEL
    COLOR  [MYCOLOR]
    OUTLINECOLOR 255 255 255
    FONT sans
    TYPE truetype
    SIZE 6
    POSITION AUTO
    PARTIALS FALSE
  END
  

  The associated RFC document for this feature is MS RFC 19: Style & Label attribute binding.

ENCODING [string]

Supported encoding format to be used for labels. If the format is not supported, the label will not be drawn. Requires the iconv library (present on most systems). The library is always detected if present on the system, but if not the label will not be drawn.

Required for displaying international characters in MapServer. More information can be found at: http://www.foss4g.org/FOSS4G/MAPSERVER/mpsnf-i18n-en.html.

FONT [name]

Font alias (as defined in the FONTSET) to use for labeling.

FORCE [true|false]

Forces labels for a particular class on, regardless of collisions. Available only for cached labels. Default is false.

MAXLENGTH [integer]

Introduced in mapserver 5.4, this keyword interacts with the WRAP keyword so that line breaks only occur after the defined number of characters

Interaction with WRAP keyword

	maxlength = 0	maxlength > 0	maxlength < 0
wrap = ‘char’	always wrap at the WRAP character	newline at the first WRAP character after MAXLENGTH characters	hard wrap (always break at exactly MAXLENGTH characters)
no wrap	no processing	skip label if it contains more than MAXLENGTH characters	hard wrap (always break at exactly MAXLENGTH characters)

The associated RFC document for this feature is MS RFC 40: Support Label Text Transformations.

MAXSIZE [integer]

Maximum font size to use when scaling text (pixels). Default is 256.

MINDISTANCE [integer]

Minimum distance between duplicate labels. Given in pixels.

MINFEATURESIZE [integer|auto]

Minimum size a feature must be to be labeled. Given in pixels. For line data the overall length of the displayed line is used, for polygons features the smallest dimension of the bounding box is used. “Auto” keyword tells MapServer to only label features that are larger than their corresponding label. Available for cached labels only.

MINSIZE [integer]

Minimum font size to use when scaling text (pixels). Default is 4.

OFFSET [x][y]

Offset values for labels, relative to the lower left hand corner of the label and the label point. Given in pixels. In the case of rotated text specify the values as if all labels are horizontal and any rotation will be compensated for.

OUTLINECOLOR [r] [g] [b] | [attribute]

• Color to draw a one pixel outline around the text.

• [Attribute] was introduced in version 5.0, to specify the item name in the attribute table to use for color values. The hard brackets [] are required. For example, if your shapefile’s DBF has a field named “MYOUTCOLOR” that holds color values for each record, your LABEL object might contain:

  LABEL
    COLOR  150 150 150
    OUTLINECOLOR [MYOUTCOLOR]
    FONT sans
    TYPE truetype
    SIZE 6
    POSITION AUTO
    PARTIALS FALSE
  END
  

  The associated RFC document for this feature is MS RFC 19: Style & Label attribute binding.

PARTIALS [true|false]

Can text run off the edge of the map? Default is true.

POSITION [ul|uc|ur|cl|cc|cr|ll|lc|lr|auto]

Position of the label relative to the labeling point (layers only). First letter is “Y” position, second letter is “X” position. “Auto” tells MapServer to calculate a label position that will not interfere with other labels. With points and polygons, MapServer selects from the 8 outer positions (i.e. excluding cc). With lines, it only uses lc or uc, until it finds a position that doesn’t collide with labels that have already been drawn. If all positions cause a conflict, then the label is not drawn (Unless the label’s FORCE a parameter is set to “true”). “Auto” placement is only available with cached labels.

PRIORITY [integer]|[item_name]

The priority parameter (added in v5.0) takes an integer value between 1 (lowest) and 10 (highest). The default value is 1. It is also possible to bind the priority to an attribute (item_name) using square brackets around the [item_name]. e.g. “PRIORITY [someattribute]”

Labels are stored in the label cache and rendered in order of priority, with the highest priority levels rendered first. Specifying an out of range PRIORITY value inside a map file will result in a parsing error. An out of range value set via MapScript or coming from a shape attribute will be clamped to the min/max values at rendering time. There is no expected impact on performance for using label priorities.

SHADOWCOLOR [r] [g] [b]

Color of drop shadow.

SHADOWSIZE [x][y]

Shadow offset in pixels.

SIZE [integer]|[tiny|small|medium|large|giant]|[attribute]

• Text size. Use “integer” to give the size in pixels of your TrueType font based label, or any of the other 5 listed keywords to bitmap fonts.

• [Attribute] was introduced in version 5.0, to specify the item name in the attribute table to use for size values. The hard brackets [] are required. For example, if your shapefile’s DBF has a field named “MYSIZE” that holds size values for each record, your LABEL object might contain:

  LABEL
    COLOR  150 150 150
    OUTLINECOLOR 255 255 255
    FONT sans
    TYPE truetype
    SIZE [MYSIZE]
    POSITION AUTO
    PARTIALS FALSE
  END
  

  The associated RFC document for this feature is MS RFC 19: Style & Label attribute binding.

TYPE [bitmap|truetype]

Type of font to use. Generally bitmap fonts are faster to draw then TrueType fonts. However, TrueType fonts are scalable and available in a variety of faces. Be sure to set the FONT parameter if you select TrueType.

WRAP [character]

Character that represents an end-of-line condition in label text, thus resulting in a multi-line label. Interacts with MAXLENGTH for conditional line wrapping after a given number of characters