Using extent indicators to enhance overview or locator maps

Extent indicators are a way to show the extent of one data frame within another data frame. This is useful when you are creating overview or locator maps. Sometimes the area that you show in your map (detail map) does not have a commonly recognized outline. To provide spatial context to the map reader, you may want to create a locator map. A locator map will show a larger area, or extent, than the detail map. This larger extent should be recognizable to the map reader. A good locator map will also contain an indicator, such as a red outline, showing where the extent of the detail map fits within this larger extent. For example, your locator map might show the location of a state (detail map extent) within a country (locator map extent).

Extent indicators are dynamic. They automatically update whenever the extent of an associated data frame (detail map or locator map) changes. Extent indicators also update when the data is rotated or when the projection is changed.

There are a number of ways you can customize the extent indicator. You can change the indicator's default red outline symbol to another color, or symbol, if you like. Or you can add a leader line and customize its display.

When Use the simple extent is checked, the extent indicator shows the geographic bounding box of the selected data frame (detail map).

Not checking Use the simple extent has three possible results:

• If the selected data frame (detail map) is being used for Data Driven Pages, then the outline of the current index feature will be used as the indicator. If point or line features are being used to drive the pages, the extent indicator will always use the simple extent.

  This behavior can be turned on or off by toggling the Use simple extent check box.

• If the selected data frame (detail map) is not being used for Data Driven Pages and is clipped, the extent indicator will show only the portion clipped.

  This behavior can be turned on or off by toggling the Use simple extent check box.

• If the data frame is neither part of Data Driven Pages nor clipped, the extent indicator will always use the simple extent.

How to use extent indicators

These steps assume that you have a map that already contains at least two data frames where one data frame's extents are completely within the extent of the other. The data frame with the larger extent is the locator map. The data frame with the smaller extent is the detail map.

1. Right-click the locator map data frame in the table of contents and click Properties.
2. Click the Extent Indicators tab on the Data Frame Properties dialog box.
3. Click the detail map data frame from the Other data frames list box.

   You are not restricted to indicating the extent of a single data frame. You can choose additional data frames if you want.

4. Click the > button to add it to the Show extent indicator for these data frames list box.
5. Click OK on all dialog boxes.

This creates an extent indicator using the default red outline.

Tip:

• You can create extent indicators for data frames that use different coordinate systems; ArcMap will automatically project the extent indicator.
• You can use extent indicators to show the positions of several different data frames on a single data frame. When you have several data frames in a map, it's helpful to name them clearly and descriptively so it's easier to know which to choose when creating an extent indicator.

How to change the symbol of extent indicators

1. Right-click the locator map data frame in the table of contents and click Properties.
2. Click the Extent Indicators tab on the Data Frame Properties dialog box.
3. Select the detail map data frame from the Show extent indicator for these data frames list box.
4. Click the Frame button.
5. Change the frame properties (color, line width, and so on) as you see fit.
6. Click OK on all dialog boxes.