Dual scale bars

Scale bars provide a visual indication of distance and feature size on the map. Dual scale bars are a special type of scale bar that show two different units together. They are associated with a map frame in a layout. As the map scale for that map frame changes, the dual scale bar updates to remain correct.

Tip:

Dual scale bars always display two scale units. To show only one scale unit, use a standard scale bar. Optionally, show scale text instead of a scale bar using dynamic text.

Insert a dual scale bar

When a scale bar is added to the page, it is automatically associated with the default map frame. If there isn't a map frame on the page, the scale bar is not associated with any map, and the map frame is set to <None>. You can set the map frame of the scale bar after it is inserted.

To insert a scale bar, follow these steps:

1. Ensure that a layout is active.

   Scale bars can be added to layout views only. They cannot be added to map views.

2. On the Insert tab, in the Map Surrounds group, click the lower half of the Scale Bar button .

   A gallery of scale bars appears.

3. Navigate to the Dual Scale Bars section of the gallery and choose a dual scale bar to add.
4. On the layout, drag to create and position the dual scale bar.
5. Optionally, right-click the newly drawn dual scale bar and choose Properties to open the Element pane. In the Element pane, set the Upper Unit and Lower Unit as desired.
6. Optionally, make any other adjustments to the Dual Scale Bar , Upper Scale Bar , and Lower Scale Bar properties in the Element pane.
7. Optionally, save the configured dual scale bar to a style for use in future layouts.

Note:

The scale bar gallery contains all scale bars in the project styles.

Modify a dual scale bar

Once you add a scale bar to the layout, you can modify it. For example, adjust the fitting strategy to determine how the scale bar reacts to changes in the map scale. Or change how the scale bar looks by adjusting the symbol for the scale bar's divisions, numbers, marks, and bars. You can also add a border, background, and shadow.

If you can't achieve the necessary appearance for a scale bar by adjusting the properties, consider converting it to graphics. To do this, right-click the scale bar in the Contents pane and choose Convert to Graphics . This changes the scale bar into groups of graphic elements that can be manipulated individually.

Caution:

Once a scale bar is converted to graphics, it loses connection to the map and no longer reacts to changes to the map scale.

A dual consists of three parts, each of which has separate editable properties. To change any of the properties, select the appropriate part in the Contents pane to view and edit the corresponding properties in the Element pane.

• Dual Scale Bar —The main element. This includes the scale bar fitting strategy options, as well as all the symbol settings for the text, division, line, and polygon symbols that make up the dual scale bar.
• Upper Scale Bar —The unit, label text, label position, division, and subdivision options for the upper scale bar unit.
• Lower Scale Bar —The unit, label text, label position, division, and subdivision options for the upper scale bar unit.

Dual scale bar settings

The scale bar fitting strategy options and the symbol options for the text, line, and polygon symbols are set on the Dual Scale Bar level . Adjustments made here apply to the symbols for both the upper and lower scale units. To adjust the dual scale bar settings, complete the following steps:

1. In the Contents pane, right-click the Dual Scale Bar and click Properties to open the Element pane.
2. In the Element pane, select the tab containing the properties you want to change.

   Options tab	Set the map frame referenced by the dual scale bar, the fitting strategy, as well as the map unit label symbology and position.
   Properties tab	Set the numbers, marks, and bar symbology.
   Display tab	Set scale bar border, background, and shadow properties.

3. Adjust the properties. To adjust the symbology of the map units, divisions, numbers, marks, and bars, click the Symbol button next to the item.

Fitting strategies

The dual scale bar fitting strategy controls how the scale bar automatically adjusts to remain accurate when the map scale changes. With some fitting strategies, when the map scale changes, the scale bar gets longer or shorter. For other strategies, the values change. Whatever values are being adjusted automatically by the fitting strategy cannot be set manually. For example, if the fitting strategy adjusts the number of divisions, that option is disabled.

There are three available fitting strategies.

Fitting strategy	Description
Adjust division value	Preserves the set number of divisions for both units and tries to preserve the scale bar width by adjusting the division values for the top and bottom units. This is the default fitting strategy, and is recommended if you want to optimize the scale bar length, without needing to display specific values. Manual resizing of the scale bar is allowed.
Adjust number of divisions	Preserves the set division values for both units and tries to preserve the scale bar width by adjusting the number of divisions. Manual resizing of the scale bar is allowed.
Adjust width	Preserves the set division values and number of divisions, for both units by adjusting the scale bar width if the map scale changes. This fitting strategy is recommend if you want to control the exact values shown for each unit in the scale bar. Manual resizing of the scale bar is not allowed.

Map units

Map units are the distance values the scale bar displays, for example, miles or kilometers. Dual scale bars have two map units, one for the upper scale bar and another for the lower scale bar. These units, and their labels, are set on the upper and lower scale bars. The text symbols and offsets for both units are always the same, so they are set for the Dual Scale Bar .

For convenience, the Upper Unit and Lower Unit drop-down lists are available on the Element pane Options tab for the Dual Scale Bar . The values are stored with the Upper Scale Bar and Lower Scale Bar , respectively, and can also be changed there.

Note:

If your desired unit is not listed, add it as a distance unit to your project.

Numbers

You can set the frequency, position, and symbol for the scale bar numbers. These options apply to all numbers shown on the scale bar. Choose an option from the Frequency drop-down list to determine where numbers are shown on your dual scale bar. There are many options available, including No labels, Single label, and Divisions.

Additional options are available to set the rounding for values, zero padding, the use of fractional characters when applicable, whether thousands separators are shown, and whether the first or last values are drawn outside the scale bar.

Marks

Marks show the scale bar divisions as lines on the bar. There are two types of marks for a dual scale bar:

• Division marks—Lines drawn at the scale bar divisions
• Subdivision marks—Lines drawn at the scale bar subdivisions

You can symbolize each mark type independently by clicking the Symbol button under the corresponding mark type and making adjustments as needed. Use the Frequency drop-down list to determine which marks are displayed.

Bar

The graphics of the scale bar itself can be modified. The available symbol properties depend on the type of scale bar added. Some scale bars are displayed as lines, while others are alternating bars. If you do not see the bar options you want, change the scale bar to a different style by selecting another dual scale bar from the Scale Bar Gallery on the Dual Scale Bar tab of the ribbon.

For line scale bars, change the symbology using the Symbol button. For stack polygon scale bars, you can set the Height value to determine how tall the bar is and choose an option from the Style drop-down menu to determine how the alternate bar symbols are shown.

Map frame and visibility range

A dual scale bar can reference any map frame on the layout. It can also be configured to display only when that map frame is within a specified scale range, which is useful when creating a map series. You can create multiple scale bars optimized for specific scales and show each only when the map frame is at that scale.

By default, a dual scale bar references the most recently selected map frame and shows at all scales. The map frame being referenced and the visible scale range can be changed at any time.

To change the associated map frame or change the visible scale range of a scale bar, complete the following steps:

1. Select the Dual Scale Bar in the Contents pane or on the layout.
2. Right-click the scale bar and click Properties to open the Element pane.
3. In the Map frame drop-down list, select the map frame for the scale bar to reference.
4. Set the visibility scale threshold using the Maximum scale and Minimum scale drop-down lists. When values are set in one or both of these lists, the dual scale bar appears only when the source map frame is within the specified scale range.

Upper and lower scale bar settings

Settings for the map unit, unit labels, divisions, and subdivisions of the scale bar are set separately for the upper and lower units. Changing one does not affect the other. To adjust the settings, complete the following steps:

1. In the Contents pane, right-click the Upper Scale Bar or Lower Scale Bar , whichever you want to adjust, and click Properties to open the Element pane.
2. Adjust the Map Unit properties.

   Map Units	The distance unit values are displayed in.
   Label Text	The text displayed to show the units, for example, KM for kilometers.
   Label Position	Where the label text is displayed relative to the scale bar.

   If your desired unit is not listed, add it as a distance unit to your project.
3. Adjust the Divisions properties.

   Division Value	The value of each scale bar division shown.
   Divisions	The number of scale bar divisions shown.
   Subdivisions	The number of subdivisions shown. These further divide the scale bar and are auto-calculated.

   The Division Value or Divisions controls are disabled for specific fitting strategies. If the fitting strategy automatically adjusts that value, it cannot be set. The Fitting Strategy read-only text shows the selected fitting strategy to provide context as to why a control is disabled. To enable the control, change the Fitting Strategy on the Dual Scale Bar.