Point symbolizer

The point symbolizer is used to style point features or centroids of non-point features.

Syntax

The full syntax of a point symbolizer is:

symbolizers:
- point:
    symbols:
    - external:
        url: <text>
        format: <text>
    - mark:
        shape: <shape>
        fill-color: <color>
        fill-opacity: <expression>
        fill-graphic:
          <graphic_options>
        stroke-color: <color>
        stroke-width: <expression>
        stroke-opacity: <expression>
        stroke-linejoin: <expression>
        stroke-linecap: <expression>
        stroke-dasharray: <float list>
        stroke-dashoffset: <expression>
        stroke-graphic:
          <graphic_options>
        stroke-graphic-fill:
          <graphic_options>
    size: <expression>
    anchor: <tuple>
    displacement: <tuple>
    opacity: <expression>
    rotation: <expression>
    geometry: <expression>
    uom: <text>
    x-labelObstacle: <boolean>
    x-composite-base: <boolean>
    x-composite: <text>

where:

Property Required? Description Default value
stroke-color No Color of line features. '#000000' (black)
stroke-width No Width of line features, measured in pixels. 1
stroke-opacity No Opacity of line features. Valid values are a decimal value between 0 (completely transparent) and 1 (completely opaque). 1
stroke-linejoin No How line segments are joined together. Options are mitre (sharp corner), round (round corner), and bevel (diagonal corner). mitre
stroke-linecap No How line features are rendered at their ends. Options are butt (sharp square edge), round (rounded edge), and square (slightly elongated square edge). butt
stroke-dasharray No A numeric list signifying length of lines and gaps, creating a dashed effect. Units are pixels, so "2 3" would be a repeating pattern of 2 pixels of drawn line followed by 3 pixels of blank space. If only one number is supplied, this will mean equal amounts of line and gap. No dash
stroke-dashoffset No Number of pixels into the dasharray to offset the drawing of the dash, used to shift the location of the lines and gaps in a dash. 0
stroke-graphic No A design or pattern to be used along the stroke. Output will always be a linear repeating pattern, and as such is not tied to the value of stroke-width. Can either be a mark consisting of a common shape or a URL that points to a graphic. The <graphic_options> should consist of a mapping containing symbols: followed by an external: or mark:, with appropriate parameters as detailed in the Point symbolizer section. Cannot be used with stroke-graphic-fill. N/A
stroke-graphic-fill No A design or pattern to be used for the fill of the stroke. The area that is to be filled is tied directly to the value of stroke-width. Can either be a mark consisting of a common shape or a URL that points to a graphic. The <graphic_options> should consist of a mapping containing symbols: followed by an external: or mark:, with appropriate parameters as detailed in the Point symbolizer section. Cannot be used with stroke-graphic. N/A
Property Required? Description Default value
fill-color No Color of inside of features. '#808080' (gray)
fill-opacity No Opacity of the fill. Valid values are a decimal value between 0 (completely transparent) and 1 (completely opaque). 1
fill-graphic No A design or pattern to be used for the fill of the feature. Can either be a mark consisting of a common shape or a URL that points to a graphic. The <graphic_options> should consist of a mapping containing symbols: followed by an external: or mark:, with appropriate parameters as detailed in the Point symbolizer section. None

The use of fill-graphic allows for the following extra options:

Property Required? Description Default value
x-graphic-margin No Used to specify margins (in pixels) around the graphic used in the fill. Possible values are a list of four (top, right, bottom, left), a list of three (top, right and left, bottom), a list of two (top and bottom, right and left), or a single value. N/A
x-random No Activates random distribution of symbols. Possible values are free or grid. free generates a completely random distribution, and grid will generate a regular grid of positions, and only randomize the position of the symbol around the cell centers, providing a more even distribution. N/A
x-random-tile-size No When used with x-random, determines the size of the grid (in pixels) that will contain the randomly distributed symbols. 256
x-random-rotation No When used with x-random, activates random symbol rotation. Possible values are none or free. none
x-random-symbol-count No When used tih x-random, determines the number of symbols drawn. Increasing this number will generate a more dense distribution of symbols 16
x-random-seed No Determines the “seed” used to generate the random distribution. Changing this value will result in a different symbol distribution. 0
Property Required? Description Default value
external No Specifies an image to use to style the point. N/A
url Yes Location of the image. Can either be an actual URL or a file path (relative to where the style file is saved in the GeoServer data directory). Should be enclosed in single quotes. N/A
format Yes Format of the image. Must be a valid MIME type (such as image/png for PNG, image/jpeg for JPG, image/svg+xml for SVG) N/A
mark No Specifies a regular shape to use to style the point. N/A
shape No Shape of the mark. Options are square, circle, triangle, cross, x, and star. square
size No Size of the mark in pixels. If the aspect ratio of the mark is not 1:1 (square), will apply to the height of the graphic only, with the width scaled proportionally. 16
anchor No Specify the center of the symbol relative to the feature location. Value is an [x,y] tuple with decimal values from 0-1, with [0,0] meaning that the symbol is anchored to the top left, and [1,1] meaning anchored to bottom right. [0.5,0.5]
displacement No Specifies a distance to which to move the symbol relative to the feature. Value is an [x,y] tuple with values expressed in pixels, so [10,5] will displace the symbol 10 pixels to the right and 5 pixels down. [0,0]
opacity No Specifies the level of transparency. Value of 0 means entirely transparent, while 1 means entirely opaque. Only affects graphics referenced by the external parameter; the opacity of mark symbols is controled by the fill-opacity and stroke-opacity of the mark. 1
rotation No Value (in degrees) or rotation of the mark. Larger values increase counter-clockwise rotation. A value of 180 will make the mark upside-down. 0
Property Required? Description Default value
geometry No Specifies which attribute to use as the geometry. First geometry attribute found (usually named geom or the_geom)
uom No Unit of measure used for width calculations pixel

The following properties are equivalent to SLD “vendor options”.

Property Required? Description Default value
x-labelObstacle No Marks the symbolizer as an obstacle such that labels drawn via a text symbolizer will not be drawn over top of these features. Options are true or false. Note that the bounding boxes of features are used when calculating obstacles, so unintended effects may occur when marking a line or polygon symbolizer as an obstacle. false
Property Required? Description Default value
x-composite No Allows for both alpha compositing and color blending options between symbolizers. N/A
x-composite-base No Allows the rendering engine to use the symbolizer mapping to define a “base” buffer for subsequent compositing and blending using x-composite. See the section on Feature Styles for more details. false

Examples

Basic point

A point symbolizer draws a point at the center of any geometry. It is defined by an external image or a symbol, either of which can be sized and rotated. A mark is a pre-defined symbol that can be drawn at the location of a point. Similar to polygons, marks have both a fill and a stroke. This example shows a point symbolizer that draws semi-transparent red diamonds with black outlines:

feature-styles:
- name: name
  rules:
  - title: red point
    symbolizers:
    - point:
        symbols:
        - mark:
            shape: square
            fill-color: '#FF0000'
            fill-opacity: 0.75
            stroke-color: '#000000'
            stroke-width: 1.5
            stroke-opacity: 1
        size: 20
        rotation: 45
../../../../_images/point_basic.png

Basic point

Point as image

Sometimes it may be useful to use an image to represent certain points. This can be accomplished using the external symbol property, which requires a url and a format. The url should be enclosed in single quotes. The format property is a MIME type image. This example shows a point symbolizer that draws an image centered on each point:

name: point
feature-styles:
- name: name
  rules:
  - symbolizers:
    - point:
        symbols:
        - external:
            url: 'geoserver.png'
            format: image/png
        size: 16
../../../../_images/point_graphic.png

Point as image

Point composition

Using more than one point symbolizer allows the composition of more complex symbology. This example shows two symbolizers along with the x-composite parameter in order to subtract a shape from a square mark, allowing the background to show through.

symbolizers:
- point:
    symbols:
    - mark:
        shape: square
        fill-color: '#222222'
    size: 40
- point:
    symbols:
    - external:
        url: 'stamp.png'
        format: image/png
    x-composite: xor
    size: 40
../../../../_images/point_composition.png

Point composition

Points as arrow heads

Sometimes it is useful to generate a point using a CQL expression. The following example generates a point at the end of each line in the shape of an arrow, rotated such that it matches the orientation of the line.

name: arrow
symbolizers:
- line:
   stroke-color: '#808080'
   stroke-width: 3
- point:
    geometry: ${endPoint(the_geom)}
    symbols:
    - mark:
        shape: shape://oarrow
        fill-color: '#808080'
    size: 30
    rotation: ${endAngle(the_geom)}
../../../../_images/arrow.png

Point as arrow head