Map within a map

Question: I am trying to blow up an area and show in on a larger map. Just like in a road atlas where the city or area is blown up to show a more detailed area. I don’t have a clue how to do this! Can someone point me in the right direction? Thanks.

Answer: You are referring to an inset map.

For a detailed review of what an inset map is and its purpose, see this Mapping Center Blog:

http://blogs.esri.com/Support/blogs/mappingcenter/archive/2008/03/04/cartographic-design-inset-maps.aspx

Here is how you can create an inset map in ArcGIS:

1.  In Layout View, insert a new data frame and rename it Inset Map.  To do this, in the top bar under Insert, select Data Frame.

2.  Resize and position the Inset Map data frame where you want it to appear on your map.

3.  Copy and paste the feature layers from the main map’s data frame into your Inset Map data frame.  To do this, you can select all of the feature layers in the main map’s data frame, right click and select Copy and then right click on the Inset Map data frame and click Paste.

4.  Use the data frame zoom and pan tools to zoom to the area that you want to show in more detail at a larger scale.

Another element that you will likely want to include in your map is an extent rectangle.  Extent rectangles are a way to show the extent of one data frame within another data frame.

To do this, first right click on the main map’s data frame and click Properties.

On the Extent Rectangles tab, under “Other data frames:”, select the data frame of your inset map.  Click the arrow to move the inset map data frame to the column on the right hand side under “Show extent rectangle for these data frames:” to show an extent rectangle for the selected data frame.

If you would like to modify the symbology of the extent rectangle (the default is a red, 4pt line width box), click on the Frame button on the right hand side.  Here you can modify the style of the extent rectangle that appears on the map.

You also have the option to create more than one inset map on a single map.  Just follow the steps outlined above for each geographic region you’d like to display at the larger scale.  You could then assign a different color for each inset map border, and then match the color of the extent rectangle to the corresponding data frame’s border color.

Formerly a Mapping Center Ask a Cartographer  Q & A.