By Charlie Frye, Esri Chief Cartographer
Indicating that a street is one-way and which way is valid to travel was a lot harder than it should have been prior to version 9.2. At 9.2, the new representations symbology makes this a much faster and easier task. To create this effect, you will need to have your street line data stored in a geodatabase which is a requirement for using representation symbology.
You will also need to have a field in your data that indicates whether a street is one-way. This also depends on the digitized direction of the street lines to align the arrows in the correct direction. If your streets are not digitized correctly, you can edit them by selecting each feature, set the Edit task to Modify Feature, then right click on the feature and choose Flip.
Start out by symbolizing your street layer using the line symbols (colors, styles, and widths) you would normally use. Don’t worry about adding arrow marker symbols to show direction for the lines. Make a copy of your street line layer and add a definition query to the copy so it only displays your one-way streets.
Create representations for your one-way streets layer (right-click on the layer in the Table of Contents and choose Convert Symbols to Representation). Open the Layer Properties and click on the Symbology tab and use these steps to set up the one-way symbols:
- Add a new marker layer to each street symbol (click where the number 1 is in the image below).
- Then change the marker placement option to “On line” by clicking where the number 2 is in the image.
- For Options (as shown below), make sure the Position is 0, Relative to is set to Line Middle, and the Angle to line option is checked.
- Click the Marker symbol and change it to an arrow. The default Esri style does not contain any arrowheads in the Representation Marker’s folder, so I created some (though explaining how to make markers is another topic and I will write about that later) and put them in a style called RepArrows.style that you can download.
- When you’re selecting the representation marker you can change its color by clicking the Properties button and then in the Marker Editor window, click on the marker, which will select it, causing its properties to show on the right, where you can change the color. Here is what the interface for my arrow looked like:
- Finally, remove the line symbol layer from your representations (the lines will be drawn with the original streets layer). To do that click on the Line tab (above that’s the squiggly line, whereas the point layer has the push-pin) and then the Remove Layer button in the row of buttons at the bottom.
Since this is representation symbology, it is stored in your database, and can be reused on any other maps that require the same solution.