Polygon symbolizer

The polygon symbolizer styles polygon (2-dimensional) features. It contains facilities for the stroke (outline) of a feature as well as the fill (inside) of a feature.

Syntax

The full syntax of a polygon symbolizer is:

symbolizers:
- polygon:
    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>
    offset: <expression>
    displacement: <expression>
    geometry: <expression>
    uom: <text>
    x-labelObstacle: <boolean>
    x-composite-base: <boolean>
    x-composite: <text>
    x-inclusion: <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

offset

No

Value in pixels for moving the drawn line relative to the location of the feature.

0

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]

Property

Required?

Description

Default value

geometry

No

Specifies which attribute to use as the geometry (see Geometry transformations in SLD)

First geometry attribute found (usually named geom or the_geom)

uom

No

Unit of measure used for width calculations (see Specifying symbolizer sizes in ground units)

pixel

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

Additional “vendor options” property for Label Obstacles:

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

Additional “vendor options” properties for Color compositing and color blending:

Additional “vendor options” properties for Color compositing and color blending:

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

Additional “vendor options” properties for Rendering Selection:

Additional “vendor options” properties for Rendering Selection:

Property

Required?

Description

Default value

x-inclusion

No

Define if rule should be included in style for legendOnly or mapOnly.

normal

Examples

Basic polygon

Polygon symbolizers have both a stroke and a fill, similar to marks for point symbolizers. The following example draws a polygon symbolizer with a red fill and black stroke with beveled line joins for the stroke:

feature-styles:
- name: name
  rules:
  - title: fill-graphic
    symbolizers:
    - polygon:
        fill-color: '#FF0000'
        fill-opacity: 0.9
        stroke-color: '#000000'
        stroke-width: 8
        stroke-opacity: 1
        stroke-linejoin: bevel
../../../../_images/polygon_basic.png

Fill with graphic

The fill-graphic property is used to fill a geometry with a repeating graphic. This can be a mark or an external image. The x-graphic-margin option can be used to specify top, right, bottom, and left margins around the graphic used in the fill. This example uses two sets of repeating squares with different offset values to draw a checkerboard pattern:

name: checkers
feature-styles:
- name: name
  rules:
  - title: fill-graphic
    symbolizers:
    - polygon:
        stroke-width: 1
        fill-graphic:
          symbols:
          - mark:
              shape: square
              fill-color: '#000000'
          size: 8
        x-graphic-margin: 16 16 0 0
    - polygon:
        stroke-width: 1
        fill-graphic:
          symbols:
          - mark:
              shape: square
              fill-color: '#000000'
          size: 8
        x-graphic-margin: 0 0 16 16
../../../../_images/polygon_checkers.png

Checkered fill

Randomized graphic fill

Normally, the graphic used for the fill-graphic property is tiled. Alternatively, one can scatter this image randomly across the fill area using the x-random option and associated other options. This could be used to create a speckled pattern, as in the following example:

name: speckles
feature-styles:
- name: name
  rules:
  - title: fill-graphic
    symbolizers:
    - polygon:
        stroke-width: 1
        fill-graphic:
          symbols:
            - mark:
                shape: circle
                fill-color: '#000000'
          size: 3
          x-random: grid
          x-random-seed: 2
          x-random-tile-size: 1000
          x-random-rotation: free
          x-random-symbol-count: 1000
../../../../_images/polygon_random.png

Randomized graphic fill

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Next: Point symbolizer