Creating line symbols
Line symbols are used to draw linear data such as transportation networks, water systems, boundaries, zonings, and other connective networks. Lines are also used to outline other features such as polygons, points, and labels. As graphics, lines can be used as borders, leaders for arrows and other annotation, and freehand drawing. Any number of layers of any line symbol type can be combined in a single line symbol. For example, a marker line can be combined with a simple line to draw a solid line with a repeating pattern of markers along it.
Line symbol types
There are four standard line types.
- Simple—Simple, fast-drawing solid lines or one-pixel-wide lines with a predefined pattern.
- Cartographic—Line symbols with properties to control repetitive dash patterns, line joins, and line caps. These symbols can be drawn offset from the geometry and can include line decorations like marker symbols along the line and/or at the line endpoints.
- Hash—Line symbols made from repeating line symbol segments. The default is hashes that draw perpendicularly to geometry, but any angle is possible.
- Marker—Line symbols made of repeating patterns of markers drawn along the geometry.
- Picture—Continuous tiling of a Windows bitmap (.bmp) or Windows enhanced metafile (.emf) graphic along the length of the line. Picture line symbols can dramatically increase draw and export time and generally do not produce aesthetically pleasing results. It is recommended that you use one of the other line symbol types instead.
Improving line symbol drawing performance
The more complexity in line symbols, the more potential for compromised drawing and export performance. Of course, this needs to be balanced with the need for the degree of detail necessary for proper cartographic depiction and communication. Simple line symbols are the fastest to draw but offer limited display options. Cartographic line symbols may draw slowly if they are constructed with a lot of complexity. Multiple layers, pattern templates, offsets, and excessive line widths will all increase draw time, for example.
In addition, combining symbol types into a multilayer symbol can slow down performance. This is because the rendering of the dataset must be cycled through once for each layer type. For example, if you combine a cartographic and hash line symbol, as is done in a basic railroad-style line symbol, the data is drawn once for the cartographic symbol and again for the hash symbol.
The ESRI_Optimized style contains symbols designed to perform better while appearing similar to their counterparts within the default ESRI style. The line symbols in the ESRI_Optimized style use fewer layers and reduced widths to improve performance.
Examples of some common line symbols
To create a symbol like this:
Use these line symbol properties:
A simple cased road
A casing drawn as a single wide symbol layer below the fill displays better at intersections and sharp angles than two offset parallel lines.
A multilane cased road
A dashed railroad symbol
A hatched railroad symbol
A directional arrow line symbol
A bicycle route symbol