Essential symbol and style vocabulary
Symbols
Symbols are graphic elements that are used in map displays. There are four basic symbol types:
- Markers are used to display point locations or embellish other symbol types.
- Line symbols are used to display linear features and boundaries.
- Fill symbols are used to fill in polygons or other areas such as map backgrounds.
- Text symbols are used to set the font, size, color, and other text properties of labels and annotation.
Styles
A style is a collection of symbols, colors, and map elements that match a theme or application domain such as transportation or geology.
Symbol level drawing
A setting that determines the drawing order of features based on their symbol properties. When symbols have more than one layer, symbol level drawing can be used to specify the order in which each layer of the symbol is drawn. Symbol level drawing can be used to refine the way that symbols interact with one another, for example, ensuring that road casings are drawn under road fills even at road intersections.
Representation
A method of illustrating data so it can be viewed and understood. In cartography, representation is used to depict likenesses of real-world features in such a way that the depictions symbolize or correspond to the real features. Representation is used to present information in a format that is viewable, storable, and transferable.
Line join
Specifies the way that cartographic line symbols are drawn at segment connections. Choices for joins are miter, round, and bevel. Miter draws an extension of the symbol edges and may be quite extended at sharp angles. Round draws a semicircle at the endpoint and is useful to ensure continuity when using multilayer cased line symbology. Bevel is similar to miter but is clipped to avoid long sharp spikes.
Line cap
Specifies the way that the endpoints of cartographic line symbols are drawn. The values available for caps are butt, round, and square. Butt stops the line symbol squarely and exactly at the line endpoint. Round extends the symbol in a semicircle past this point. Square extends the line symbol half the symbol width beyond the endpoint.
Offset
The distance away from the line feature geometry that a line symbol is drawn.
Template
Specifies the repeating pattern of dashes or markers along cartographic line symbols.
Mask
In digital cartography, a means of covering or hiding features on a map to enhance cartographic representation. For example, masking is often used to cover features behind text to make the text more readable.