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Map elements

The following is a list of properties provided in CartoCSS that you can apply to map elements.

All elements

image-filters functions

Default Value: none (no filters) A list of image filters.

comp-op clear src dst src-over dst-over src-in dst-in src-out dst-out src-atop dst-atop xor plus minus multiply screen overlay darken lighten color-dodge color-burn hard-light soft-light difference exclusion contrast invert invert-rgb grain-merge grain-extract hue saturation color value

Default Value: src-over (add the current layer on top of other layers) Composite operation. This defines how this layer should behave relative to layers atop or below it.

opacity float

Default Value: 1 (no separate buffer will be used and no alpha will be applied to the style after rendering) An alpha value for the style (which means an alpha applied to all features in separate buffer and then composited back to main buffer)

map

background-color color

Default Value: none (transparent) Map Background color

background-image uri

Default Value: (transparent) An image that is repeated below all features on a map as a background.

srs string

Default Value: +proj=longlat +ellps=WGS84 +datum=WGS84 +no_defs (The proj4 literal of EPSG:4326 is assumed to be the Map's spatial reference and all data from layers within this map will be plotted using this coordinate system. If any layers do not declare an srs value then they will be assumed to be in the same srs as the Map and not transformations will be needed to plot them in the Map's coordinate space) Map spatial reference (proj4 string)

buffer-size float

Default Value: 0 (No buffer will be used) Extra tolerance around the map (in pixels) used to ensure labels crossing tile boundaries are equally rendered in each tile (e.g. cut in each tile). Not intended to be used in combination with "avoid-edges".

base string

Default Value: (This base path defaults to an empty string meaning that any relative paths to files referenced in styles or layers will be interpreted relative to the application process.) Any relative paths used to reference files will be understood as relative to this directory path if the map is loaded from an in memory object rather than from the filesystem. If the map is loaded from the filesystem and this option is not provided it will be set to the directory of the stylesheet.

font-directory uri

Default Value: none (No map-specific fonts will be registered) Path to a directory which holds fonts which should be registered when the Map is loaded (in addition to any fonts that may be automatically registered).

polygon

polygon-fill color

Default Value: rgba(128,128,128,1) (gray and fully opaque (alpha = 1), same as rgb(128,128,128)) Fill color to assign to a polygon

polygon-opacity float

Default Value: 1 (opaque) The opacity of the polygon

polygon-gamma float

Default Value: 1 (fully antialiased) Range: 0-1 Level of antialiasing of polygon edges

polygon-gamma-method power linear none threshold multiply

Default Value: power (pow(x,gamma) is used to calculate pixel gamma, which produces slightly smoother line and polygon antialiasing than the 'linear' method, while other methods are usually only used to disable AA) An Antigrain Geometry specific rendering hint to control the quality of antialiasing. Under the hood in Mapnik this method is used in combination with the 'gamma' value (which defaults to 1). The methods are in the AGG source at https://github.com/mapnik/mapnik/blob/master/deps/agg/include/agg_gamma_functions.h

polygon-clip boolean

Default Value: true (geometry will be clipped to map bounds before rendering) geometries are clipped to map bounds by default for best rendering performance. In some cases users may wish to disable this to avoid rendering artifacts.

polygon-smooth float

Default Value: 0 (no smoothing) Range: 0-1 Smooths out geometry angles. 0 is no smoothing, 1 is fully smoothed. Values greater than 1 will produce wild, looping geometries.

polygon-geometry-transform functions

Default Value: none (geometry will not be transformed) Allows transformation functions to be applied to the geometry.

polygon-comp-op clear src dst src-over dst-over src-in dst-in src-out dst-out src-atop dst-atop xor plus minus multiply screen overlay darken lighten color-dodge color-burn hard-light soft-light difference exclusion contrast invert invert-rgb grain-merge grain-extract hue saturation color value

Default Value: src-over (add the current symbolizer on top of other symbolizer) Composite operation. This defines how this symbolizer should behave relative to symbolizers atop or below it.

line

line-color color

Default Value: rgba(0,0,0,1) (black and fully opaque (alpha = 1), same as rgb(0,0,0)) The color of a drawn line

line-width float

Default Value: 1 The width of a line in pixels

line-opacity float

Default Value: 1 (opaque) The opacity of a line

line-join miter round bevel

Default Value: miter The behavior of lines when joining

line-cap butt round square

Default Value: butt The display of line endings

line-gamma float

Default Value: 1 (fully antialiased) Range: 0-1 Level of antialiasing of stroke line

line-gamma-method power linear none threshold multiply

Default Value: power (pow(x,gamma) is used to calculate pixel gamma, which produces slightly smoother line and polygon antialiasing than the 'linear' method, while other methods are usually only used to disable AA) An Antigrain Geometry specific rendering hint to control the quality of antialiasing. Under the hood in Mapnik this method is used in combination with the 'gamma' value (which defaults to 1). The methods are in the AGG source at https://github.com/mapnik/mapnik/blob/master/deps/agg/include/agg_gamma_functions.h

line-dasharray numbers

Default Value: none (solid line) A pair of length values [a,b], where (a) is the dash length and (b) is the gap length respectively. More than two values are supported for more complex patterns.

line-dash-offset numbers

Default Value: none (solid line) valid parameter but not currently used in renderers (only exists for experimental svg support in Mapnik which is not yet enabled)

line-miterlimit float

Default Value: 4 (Will auto-convert miters to bevel line joins when theta is less than 29 degrees as per the SVG spec: 'miterLength / stroke-width = 1 / sin ( theta / 2 )') The limit on the ratio of the miter length to the stroke-width. Used to automatically convert miter joins to bevel joins for sharp angles to avoid the miter extending beyond the thickness of the stroking path. Normally will not need to be set, but a larger value can sometimes help avoid jaggy artifacts.

line-clip boolean

Default Value: true (geometry will be clipped to map bounds before rendering) geometries are clipped to map bounds by default for best rendering performance. In some cases users may wish to disable this to avoid rendering artifacts.

line-smooth float

Default Value: 0 (no smoothing) Range: 0-1 Smooths out geometry angles. 0 is no smoothing, 1 is fully smoothed. Values greater than 1 will produce wild, looping geometries.

line-offset float

Default Value: 0 (no offset) Offsets a line a number of pixels parallel to its actual path. Postive values move the line left, negative values move it right (relative to the directionality of the line).

line-rasterizer full fast

Default Value: full Exposes an alternate AGG rendering method that sacrifices some accuracy for speed.

line-geometry-transform functions

Default Value: none (geometry will not be transformed) Allows transformation functions to be applied to the geometry.

line-comp-op clear src dst src-over dst-over src-in dst-in src-out dst-out src-atop dst-atop xor plus minus multiply screen overlay darken lighten color-dodge color-burn hard-light soft-light difference exclusion contrast invert invert-rgb grain-merge grain-extract hue saturation color value

Default Value: src-over (add the current symbolizer on top of other symbolizer) Composite operation. This defines how this symbolizer should behave relative to symbolizers atop or below it.

markers

marker-file uri

Default Value: (An ellipse or circle, if width equals height) An SVG file that this marker shows at each placement. If no file is given, the marker will show an ellipse.

marker-opacity float

Default Value: 1 (The stroke-opacity and fill-opacity will be used) The overall opacity of the marker, if set, overrides both the opacity of both the fill and stroke

marker-fill-opacity float

Default Value: 1 (opaque) The fill opacity of the marker

marker-line-color color

Default Value: black The color of the stroke around a marker shape.

marker-line-width float

The width of the stroke around a marker shape, in pixels. This is positioned on the boundary, so high values can cover the area itself.

marker-line-opacity float

Default Value: 1 (opaque) The opacity of a line

marker-placement point line interior

Default Value: point (Place markers at the center point (centroid) of the geometry) Attempt to place markers on a point, in the center of a polygon, or if markers-placement:line, then multiple times along a line. 'interior' placement can be used to ensure that points placed on polygons are forced to be inside the polygon interior

marker-type arrow ellipse

Default Value: ellipse The default marker-type. If a SVG file is not given as the marker-file parameter, the renderer provides either an arrow or an ellipse (a circle if height is equal to width)

marker-width expression

Default Value: 10 The width of the marker, if using one of the default types.

marker-height expression

Default Value: 10 The height of the marker, if using one of the default types.

marker-fill color

Default Value: blue The color of the area of the marker.

marker-allow-overlap boolean

Default Value: false (Do not allow makers to overlap with each other - overlapping markers will not be shown.) Control whether overlapping markers are shown or hidden.

marker-ignore-placement boolean

Default Value: false (do not store the bbox of this geometry in the collision detector cache) value to control whether the placement of the feature will prevent the placement of other features

marker-spacing float

Default Value: 100 Space between repeated labels

marker-max-error float

Default Value: 0.2 The maximum difference between actual marker placement and the marker-spacing parameter. Setting a high value can allow the renderer to try to resolve placement conflicts with other symbolizers.

marker-transform functions

Default Value: (No transformation) SVG transformation definition

marker-clip boolean

Default Value: true (geometry will be clipped to map bounds before rendering) geometries are clipped to map bounds by default for best rendering performance. In some cases users may wish to disable this to avoid rendering artifacts.

marker-smooth float

Default Value: 0 (no smoothing) Range: 0-1 Smooths out geometry angles. 0 is no smoothing, 1 is fully smoothed. Values greater than 1 will produce wild, looping geometries.

marker-geometry-transform functions

Default Value: none (geometry will not be transformed) Allows transformation functions to be applied to the geometry.

marker-comp-op clear src dst src-over dst-over src-in dst-in src-out dst-out src-atop dst-atop xor plus minus multiply screen overlay darken lighten color-dodge color-burn hard-light soft-light difference exclusion contrast invert invert-rgb grain-merge grain-extract hue saturation color value

Default Value: src-over (add the current symbolizer on top of other symbolizer) Composite operation. This defines how this symbolizer should behave relative to symbolizers atop or below it.

shield

shield-name expression

Value to use for a shield"s text label. Data columns are specified using brackets like [column_name]

shield-file uri

Default Value: none Image file to render behind the shield text

shield-face-name string

Default Value: Font name and style to use for the shield text

shield-unlock-image boolean

Default Value: false (text alignment relative to the shield image uses the center of the image as the anchor for text positioning.) This parameter should be set to true if you are trying to position text beside rather than on top of the shield image

shield-size float

The size of the shield text in pixels

shield-fill color

The color of the shield text

shield-placement point line vertex interior

Default Value: point How this shield should be placed. Point placement attempts to place it on top of points, line places along lines multiple times per feature, vertex places on the vertexes of polygons, and interior attempts to place inside of polygons.

shield-avoid-edges boolean

Default Value: false Tell positioning algorithm to avoid labeling near intersection edges.

shield-allow-overlap boolean

Default Value: false (Do not allow shields to overlap with other map elements already placed.) Control whether overlapping shields are shown or hidden.

shield-min-distance float

Default Value: 0 Minimum distance to the next shield symbol, not necessarily the same shield.

shield-spacing float

Default Value: 0 The spacing between repeated occurrences of the same shield on a line

shield-min-padding float

Default Value: 0 Determines the minimum amount of padding that a shield gets relative to other shields

shield-wrap-width unsigned

Default Value: 0 Length of a chunk of text in characters before wrapping text

shield-wrap-before boolean

Default Value: false Wrap text before wrap-width is reached. If false, wrapped lines will be a bit longer than wrap-width.

shield-wrap-character string

Default Value: Use this character instead of a space to wrap long names.

shield-halo-fill color

Default Value: #FFFFFF (white) Specifies the color of the halo around the text.

shield-halo-radius float

Default Value: 0 (no halo) Specify the radius of the halo in pixels

shield-character-spacing unsigned

Default Value: 0 Horizontal spacing between characters (in pixels). Currently works for point placement only, not line placement.

shield-line-spacing unsigned

Vertical spacing between lines of multiline labels (in pixels)

shield-text-dx float

Default Value: 0 Displace text within shield by fixed amount, in pixels, +/- along the X axis. A positive value will shift the text right

shield-text-dy float

Default Value: 0 Displace text within shield by fixed amount, in pixels, +/- along the Y axis. A positive value will shift the text down

shield-dx float

Default Value: 0 Displace shield by fixed amount, in pixels, +/- along the X axis. A positive value will shift the text right

shield-dy float

Default Value: 0 Displace shield by fixed amount, in pixels, +/- along the Y axis. A positive value will shift the text down

shield-opacity float

Default Value: 1 (Default 1.0) - opacity of the image used for the shield

shield-text-opacity float

Default Value: 1 (Default 1.0) - opacity of the text placed on top of the shield

shield-horizontal-alignment left middle right auto

Default Value: auto The shield's horizontal alignment from its centerpoint

shield-vertical-alignment top middle bottom auto

Default Value: middle The shield's vertical alignment from its centerpoint

shield-text-transform none uppercase lowercase capitalize

Default Value: none Transform the case of the characters

shield-justify-alignment left center right auto

Default Value: auto Define how text in a shield's label is justified

shield-clip boolean

Default Value: true (geometry will be clipped to map bounds before rendering) geometries are clipped to map bounds by default for best rendering performance. In some cases users may wish to disable this to avoid rendering artifacts.

shield-comp-op clear src dst src-over dst-over src-in dst-in src-out dst-out src-atop dst-atop xor plus minus multiply screen overlay darken lighten color-dodge color-burn hard-light soft-light difference exclusion contrast invert invert-rgb grain-merge grain-extract hue saturation color value

Default Value: src-over (add the current symbolizer on top of other symbolizer) Composite operation. This defines how this symbolizer should behave relative to symbolizers atop or below it.

line-pattern

line-pattern-file uri

Default Value: none An image file to be repeated and warped along a line

line-pattern-clip boolean

Default Value: true (geometry will be clipped to map bounds before rendering) geometries are clipped to map bounds by default for best rendering performance. In some cases users may wish to disable this to avoid rendering artifacts.

line-pattern-smooth float

Default Value: 0 (no smoothing) Range: 0-1 Smooths out geometry angles. 0 is no smoothing, 1 is fully smoothed. Values greater than 1 will produce wild, looping geometries.

line-pattern-geometry-transform functions

Default Value: none (geometry will not be transformed) Allows transformation functions to be applied to the geometry.

line-pattern-comp-op clear src dst src-over dst-over src-in dst-in src-out dst-out src-atop dst-atop xor plus minus multiply screen overlay darken lighten color-dodge color-burn hard-light soft-light difference exclusion contrast invert invert-rgb grain-merge grain-extract hue saturation color value

Default Value: src-over (add the current symbolizer on top of other symbolizer) Composite operation. This defines how this symbolizer should behave relative to symbolizers atop or below it.

polygon-pattern

polygon-pattern-file uri

Default Value: none Image to use as a repeated pattern fill within a polygon

polygon-pattern-alignment local global

Default Value: local Specify whether to align pattern fills to the layer or to the map.

polygon-pattern-gamma float

Default Value: 1 (fully antialiased) Range: 0-1 Level of antialiasing of polygon pattern edges

polygon-pattern-opacity float

Default Value: 1 (The image is rendered without modifications) (Default 1.0) - Apply an opacity level to the image used for the pattern

polygon-pattern-clip boolean

Default Value: true (geometry will be clipped to map bounds before rendering) geometries are clipped to map bounds by default for best rendering performance. In some cases users may wish to disable this to avoid rendering artifacts.

polygon-pattern-smooth float

Default Value: 0 (no smoothing) Range: 0-1 Smooths out geometry angles. 0 is no smoothing, 1 is fully smoothed. Values greater than 1 will produce wild, looping geometries.

polygon-pattern-geometry-transform functions

Default Value: none (geometry will not be transformed) Allows transformation functions to be applied to the geometry.

polygon-pattern-comp-op clear src dst src-over dst-over src-in dst-in src-out dst-out src-atop dst-atop xor plus minus multiply screen overlay darken lighten color-dodge color-burn hard-light soft-light difference exclusion contrast invert invert-rgb grain-merge grain-extract hue saturation color value

Default Value: src-over (add the current symbolizer on top of other symbolizer) Composite operation. This defines how this symbolizer should behave relative to symbolizers atop or below it.

raster

raster-opacity float

Default Value: 1 (opaque) The opacity of the raster symbolizer on top of other symbolizers.

raster-filter-factor float

Default Value: -1 (Allow the datasource to choose appropriate downscaling.) This is used by the Raster or Gdal datasources to pre-downscale images using overviews. Higher numbers can sometimes cause much better scaled image output, at the cost of speed.

raster-scaling near fast bilinear bilinear8 bicubic spline16 spline36 hanning hamming hermite kaiser quadric catrom gaussian bessel mitchell sinc lanczos blackman

Default Value: near The scaling algorithm used to making different resolution versions of this raster layer. Bilinear is a good compromise between speed and accuracy, while lanczos gives the highest quality.

raster-mesh-size unsigned

Default Value: 16 (Reprojection mesh will be 1/16 of the resolution of the source image) A reduced resolution mesh is used for raster reprojection, and the total image size is divided by the mesh-size to determine the quality of that mesh. Values for mesh-size larger than the default will result in faster reprojection but might lead to distortion.

raster-comp-op clear src dst src-over dst-over src-in dst-in src-out dst-out src-atop dst-atop xor plus minus multiply screen overlay darken lighten color-dodge color-burn hard-light soft-light difference exclusion contrast invert invert-rgb grain-merge grain-extract hue saturation color value

Default Value: src-over (add the current symbolizer on top of other symbolizer) Composite operation. This defines how this symbolizer should behave relative to symbolizers atop or below it.

point

point-file uri

Default Value: none Image file to represent a point

point-allow-overlap boolean

Default Value: false (Do not allow points to overlap with each other - overlapping markers will not be shown.) Control whether overlapping points are shown or hidden.

point-ignore-placement boolean

Default Value: false (do not store the bbox of this geometry in the collision detector cache) value to control whether the placement of the feature will prevent the placement of other features

point-opacity float

Default Value: 1 (Fully opaque) A value from 0 to 1 to control the opacity of the point

point-placement centroid interior

Default Value: centroid How this point should be placed. Centroid calculates the geometric center of a polygon, which can be outside of it, while interior always places inside of a polygon.

point-transform functions

Default Value: (No transformation) SVG transformation definition

point-comp-op clear src dst src-over dst-over src-in dst-in src-out dst-out src-atop dst-atop xor plus minus multiply screen overlay darken lighten color-dodge color-burn hard-light soft-light difference exclusion contrast invert invert-rgb grain-merge grain-extract hue saturation color value

Default Value: src-over (add the current symbolizer on top of other symbolizer) Composite operation. This defines how this symbolizer should behave relative to symbolizers atop or below it.

text

text-name expression

Default Value: Value to use for a text label. Data columns are specified using brackets like [column_name]

text-face-name string

Font name and style to render a label in

text-size float

Default Value: 10 Text size in pixels

text-ratio unsigned

Default Value: 0 Define the amount of text (of the total) present on successive lines when wrapping occurs

text-wrap-width unsigned

Default Value: 0 Length of a chunk of text in characters before wrapping text

text-wrap-before boolean

Default Value: false Wrap text before wrap-width is reached. If false, wrapped lines will be a bit longer than wrap-width.

text-wrap-character string

Default Value: Use this character instead of a space to wrap long text.

text-spacing unsigned

Distance between repeated text labels on a line (aka. label-spacing)

text-character-spacing float

Default Value: 0 Horizontal spacing adjustment between characters in pixels

text-line-spacing unsigned

Default Value: 0 Vertical spacing adjustment between lines in pixels

text-label-position-tolerance unsigned

Default Value: 0 Allows the label to be displaced from its ideal position by a number of pixels (only works with placement:line)

text-max-char-angle-delta float

Default Value: 22.5 The maximum angle change, in degrees, allowed between adjacent characters in a label. This value internally is converted to radians to the default is 22.5*math.pi/180.0. The higher the value the fewer labels will be placed around around sharp corners.

text-fill color

Default Value: #000000 Specifies the color for the text

text-opacity float

Default Value: 1 (Fully opaque) A number from 0 to 1 specifying the opacity for the text

text-halo-fill color

Default Value: #FFFFFF (white) Specifies the color of the halo around the text.

text-halo-radius float

Default Value: 0 (no halo) Specify the radius of the halo in pixels

text-dx float

Default Value: 0 Displace text by fixed amount, in pixels, +/- along the X axis. A positive value will shift the text right

text-dy float

Default Value: 0 Displace text by fixed amount, in pixels, +/- along the Y axis. A positive value will shift the text down

text-vertical-alignment top middle bottom auto

Default Value: auto (Default affected by value of dy; "bottom" for dy>0, "top" for dy<0.) Position of label relative to point position.

text-avoid-edges boolean

Default Value: false Tell positioning algorithm to avoid labeling near intersection edges.

text-min-distance float

Minimum permitted distance to the next text symbolizer.

text-min-padding float

Determines the minimum amount of padding that a text symbolizer gets relative to other text

text-min-path-length float

Default Value: 0 (place labels on all paths) Place labels only on paths longer than this value.

text-allow-overlap boolean

Default Value: false (Do not allow text to overlap with other text - overlapping markers will not be shown.) Control whether overlapping text is shown or hidden.

text-orientation expression

Rotate the text.

text-placement point line vertex interior

Default Value: point Control the style of placement of a point versus the geometry it is attached to.

text-placement-type dummy simple list

Default Value: dummy Re-position and/or re-size text to avoid overlaps. "simple" for basic algorithm (using text-placements string,) "dummy" to turn this feature off.

text-placements string

Default Value: If "placement-type" is set to "simple", use this "POSITIONS,[SIZES]" string. An example is `text-placements: "E,NE,SE,W,NW,SW";`

text-transform none uppercase lowercase capitalize

Default Value: none Transform the case of the characters

text-horizontal-alignment left middle right auto

Default Value: auto The text's horizontal alignment from its centerpoint

text-align left right center auto

Default Value: auto (Auto alignment means that text will be centered by default except when using the `placement-type` parameter - in that case either right or left justification will be used automatically depending on where the text could be fit given the `text-placements` directives) Define how text is justified

text-clip boolean

Default Value: true (geometry will be clipped to map bounds before rendering) geometries are clipped to map bounds by default for best rendering performance. In some cases users may wish to disable this to avoid rendering artifacts.

text-comp-op clear src dst src-over dst-over src-in dst-in src-out dst-out src-atop dst-atop xor plus minus multiply screen overlay darken lighten color-dodge color-burn hard-light soft-light difference exclusion contrast invert invert-rgb grain-merge grain-extract hue saturation color value

Default Value: src-over (add the current symbolizer on top of other symbolizer) Composite operation. This defines how this symbolizer should behave relative to symbolizers atop or below it.

building

building-fill color

Default Value: #FFFFFF The color of the buildings walls.

building-fill-opacity float

Default Value: 1 The opacity of the building as a whole, including all walls.

building-height expression

Default Value: 0 The height of the building in pixels.

Values

Below is a list of values and an explanation of any expression that can be applied to properties in CartCSS.

Color

CartoCSS accepts a variety of syntaxes for colors - HTML-style hex values, rgb, rgba, and hsl. It also supports the predefined HTML colors names, like yellow and blue.

#line {
line-color: #ff0;
line-color: #ffff00;
line-color: rgb(255, 255, 0);
line-color: rgba(255, 255, 0, 1);
line-color: hsl(100, 50%, 50%);
line-color: yellow;
}

Especially of note is the support for hsl, which can be easier to reason about than rgb()

Carto also includes several color functions borrowed from less:

// lighten and darken colors
lighten(#ace, 10%);
darken(#ace, 10%);

// saturate and desaturate
saturate(#550000, 10%);
desaturate(#00ff00, 10%);

// increase or decrease the opacity of a color
fadein(#fafafa, 10%);
fadeout(#fefefe, 14%);

// spin rotates a color around the color wheel by degrees
spin(#ff00ff, 10);

// mix generates a color in between two other colors.
mix(#fff, #000, 50%);

These functions all take arguments which can be color variables, literal colors, or the results of other functions operating on colors.

Float

Float is a fancy way of saying 'number'. In CartoCSS, you specify just a number - unlike CSS, there are no units, but everything is specified in pixels.

#line {
line-width: 2;
}

It's also possible to do simple math with number values:

#line {
line-width: 4 / 2; // division
line-width: 4 + 2; // addition
line-width: 4 - 2; // subtraction
line-width: 4 * 2; // multiplication
line-width: 4 % 2; // modulus
}

URI

URI is a fancy way of saying URL. When an argument is a URI, you use the same kind of url('place.png') notation that you would with HTML. Quotes around the URL aren't required, but are highly recommended.

URIs can be paths to places on your computer, or on the internet.

#markers {
marker-file: url('marker.png');
}

String

A string is basically just text. In the case of CartoCSS, you're going to put it in quotes. Strings can be anything, though pay attention to the cases of text-name and shield-name - they actually will refer to features, which you refer to by putting them in brackets, as seen in the example below.

#labels {
text-name: "[MY_FIELD]";
}

Boolean

Boolean means yes or no, so it accepts the values true or false.

#markers {
marker-allow-overlap:true;
}

Expressions

Expressions are statements that can include fields, numbers, and other types in a really flexible way. You have run into expressions before, in the realm of 'fields', where you'd specify "[FIELD]", but expressions allow you to drop the quotes and also do quick addition, division, multiplication, and concatenation from within Carto syntax.

#buildings {
building-height: [HEIGHT_FIELD] * 10;
}

Numbers

Numbers are comma-separated lists of one or more number in a specific order. They're used in line dash arrays, in which the numbers specify intervals of line, break, and line again.

#disputedboundary {
line-dasharray: 1, 4, 2;
}

Percentages

In Carto, the percentage symbol, % universally means value/100. It's meant to be used with ratio-related properties, like opacity rules.

You should not use percentages as widths, heights, or other properties - unlike CSS, percentages are not relative to cascaded classes or page size, they're, as stated, simply the value divided by one hundred.

#world {
// this syntax
polygon-opacity: 50%;

// is equivalent to
polygon-opacity: 0.5;
}

Functions

Functions are comma-separated lists of one or more functions. For instance, transforms use the functions type to allow for transforms within Carto, which are optionally chainable.

#point {
point-transform: scale(2, 2);
}