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.

Tip:

The Template tab (found on the properties of all line symbols except simple line symbols) lets you design a common template for the symbol layers that will be layered. Use the same template to stack and center line dashes with markers, or you can reverse the template pattern to center the marker in the gap. For hash lines, the template mark indicates how many dashes will occur in the pattern segment. You can also align multiple line layers by synchronizing template settings.

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	Two symbol layers, both Cartographic Line Symbol type. The bottom layer (the casing) should be wider and typically a dark color, like black. The top layer (the fill) is slightly narrower and typically a bright color. Round line joins on both symbol layers to ensure good connections at angles. Tip: 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	Three symbol layers, all Cartographic Line Symbol type. The bottom layer (the casing) should be wider and typically a dark color, like black. The middle layer (the fill) is slightly narrower and typically a bright color. The top layer indicates the multilane and is generally much thinner and the same color as the casing layer. Round line joins on both symbol layers to ensure good connections at angles.
A dashed railroad symbol	Two symbol layers, both Cartographic Line Symbol type. The bottom layer (the casing) should be wider and typically black. The top layer (the fill) is narrower and typically white. The second (white) layer has a Template of one square on, one square off, and an Interval of 8 pts. Line caps are Butt. Round line joins on both symbol layers to ensure good connections at angles.
A hatched railroad symbol	Two symbol layers, one Cartographic Line Symbol type, the other Hash Line Symbol type, both typically the same color. The Hash layer has a Template of one square on, four squares off, and an Interval of 2 pts. The Cartographic Line properties within the Hash layer include 5-pt Width and Butt Line Caps.
A directional arrow line symbol	A single symbol layer of Cartographic Line Symbol type and another Hash Line Symbol type, both typically the same color. The hash layer has a Template of one square on, four squares off, and an Interval of 2 pts. The Cartographic Line properties within the Hash layer include 5-pt Width and Butt Line Caps.
A bicycle route symbol	Two symbol layers, one Cartographic Line Symbol type, the other Marker Line Symbol type. The marker layer has a Template of one square on, nine squares off, and an Interval of 3 pts. The Marker Line symbol is a three-layer character marker symbol. The bottom two layers are made from the Unicode 190 glyph (a rounded square) in the ESRI Default Marker font. The first is black, size 12 pt. The second is green, size 11 pt. The third marker symbol layer is made from Unicode 189 (a stylized cyclist), white, size 10.