Creating a Map Layout from Start to Finish - All About Legends

Primary tabs

Customizing Legends Using the Legend Properties

The general purpose of the legend is to define the symbols used in your map. As we will explore in the next section, all map data which is not an image or a basemap is represented by a symbol, and that symbol should be represented in the legend. As new cartographers, you should use a legend for each data frame and each legend should include a representation of each symbol that is important to understanding the map and a reader friendly description. It is not necessary to include every layer on your map, as some are used as reference such as state lines in a thematic map showing average population by state. A reader would expect the colors used to appear in the legend, yet “State Lines” is rather obvious in a map titled “Average Population by State”. As with neatlines, when your cartographic skills progress, the use of legends will become symbol and map dependent.

In most GIS software, ArcGIS included, layers can be renamed with a reader friendly alias to keep data organized while you are working with it as well as in the legend. A reader will better understand your map (and it will look much nicer) if the legend reads “Major Rivers” instead of “rivers_clip_JeffCo”. In ArcGIS, aliases can be assigned by slow left clicking on the name in the Table of Contents, which will allow you to type a new name or via the General tab of the Layer Properties.

An example of a legend where care was not taken to make reader friendly labels.An example of a legend with reader friendly labels

Adding and Changing Legends in ArcMap

While adding a legend in ArcMap is as easy as selecting “Legend” from the Insert menu and clicking “Next” in the resulting wizard, making a quality legend takes a little bit more time. In this section, we will add a legend, change the display names to “reader friendly” labels, adjust what shows for each item (layer name, heading, labels, and descriptions), change the swatch pattern, and look at the benefits and setbacks of converting your legend to a graphic.

Use the Legend Wizard to Add a Legend

  1. Active the data frame for which the legend will be made.
  2. From the Insert menu, select “Legend” to launch the Legend Wizard
  1. In the first screen of the wizard, use the left/right arrows to add or remove layers to/from the legend. ArcMap will automatically add any visible layer, and it’s up to you to decide which ones to exclude. You often want to remove any layers that are used for reference in an obvious way (ie. state lines)
  2. Use the up/down arrows to reorder the items. In general, you should include layers that express your ideas at the top of the legend while any reference layers you’ve decided to include at the bottom. While there is no rule, legends often show points at the top, polylines in the middle, and polygons at the bottom.
    These options can be adjusted later by double-clicking on the finished legend.
  1. Change the title of the legend if needed. Most often, the name of “Legend” is rather obvious and should be excluded. However, there are times when it should be named something custom to the map’s subject.
    These options can be adjusted later by double-clicking on the finished legend.
  1. Add a border and background the legend, if needed. Legends often have a border and will have a background if it is placed on top of darker data or the basemap.
    These options can be adjusted later by double-clicking on the finished legend.
  1. For each layer, if desired, adjust the line or area shape to match the features. Be careful with these options; too much variation will look sloppy and detract from the few items you may want to emphasis. If there is no solid reason to adjust these, they should be generally left as the default.
    These options, like all of the others, can be adjusted later by double-clicking on the finished legend.
  1. The final screen allows you to adjust all of the legend spacing. By clicking inside one the boxes, it the graphic will change to show you where changing that number will take place. While you are still learning ArcMap’s layout view, it’s best to just leave all of these as the default.
  1. Lastly, finish the wizard to add the legend to the map and use the “General” tab of the Layer Properties to give each layer a reader friendly name.

Non-reader friendly names

Reader friendly names

Adjust Additional Legend Settings

In addition to changing all of the settings found in the legend wizard after the legend has been created, there are some additional options in the Legend Properties to make it just right. Once the Legend has been created in the Layout view, double click to launch the Properties

Adjusting Individual Legend Items

Once the legend is made, the layer name can be changed to a readable version in the Table of Contents (number nine above). However, when the symbology is set to use a field to clasifly data, that field name is shown in the Legend. It's possible to get rid of that field heading with just a few clicks.

Changing Legend Feature Labels

The displayed legend feature labels can be changed within the Symbology tab. This is useful when adding layers to a Legend. Even though a layer might have an precision solved to nine decimal places, that is often overwhelming for the reader. When layers use coded values to represent features, the labels will automatically show those coded values. In order to explain the code to the reader, the labels can be changed without the need of creating/populating new fields

General Tab

In the “General” tab, you can adjust the legend’s title, the layers participating in the legend, and the order which they appear.

  • Once you’ve put your layers in the order you wish them to appear, uncheck the “Reorder the legend items when the map layers are reordered” option. This will hold them even if you change the drawing order.
  • Occasionally, you might need to have a legend item for a layer not being displayed. To accomplish this, uncheck the “Only display layers that are checked on in the Table of Contents” box. Then you can add additional layers from the “Map Layers” to the “Legend Items”.
  • To prevent new legend items from appearing when a new layer is added to a data frame, uncheck the “Add a new item to the legend when a new layer is added to the map” box.

Items Tab

The “Items” tab will allow you to adjust variables for each of the layers independently as well as those to adjust variables to apply to the way all items sit in the legend. For example, each layer can be set to show the layer name, items labels, the field heading (if the layer is being displayed by classes or unique values), or the items descriptions (if applicable). The patch can be defined for each layer in this view, as well as the choice of how to arrange the patch, label, and description.

Options for adjusting variable that effect all the items together, such as the font (which can also be changed for each layer independently) and the ability to limit the legend to only layers visible in the current extent can be found in the items tab.

Layout Tab

The “Layout” tab controls the gap distanced between the different parts of the legend, the default patch type, width, and height, text wrapping, and fixed frame options. The gap distances (which are very large in the example due to the example legend being very large for screenshotting) are the same ones that were in the last page of the wizard. Adjusting each value will adjust a different distance. By clicking on a value, the graphic will change, showing where the change will effect the legend.

The default patch line, area, width, and height will change all of the patches in the legend vs the Items tab which allows for individual item adjustments.

Text wrapping will control how the labels and descriptions will wrap if they are too long to neatly fit.

The “Fitting Strategy” will control how the columns and contents will react when the frame size (found in “Size and Position”) is changed. To define a fixed frame (one that cannot be changed by dragging a corner of the legend) in the Size and Position tab, first mark this box.

Frame Tab

The “Frame” tab will control the border, background, and drop shadow for the legend. The “XY Gap” (defined independently for the border and the background) will create more space between the items in the legend and the border/background. X Gap will increase the left/right space while the Y Gap will increase the top/bottom space. Rounding will control the rounding of the corners, again, dependently for the border and background.

“Draft mode - just show name” will hide the legend items, leaving just the background and border (if applicable) and the word “Legend”. This can help the drawing time of the layout, similar to “Toggle Draft Mode” in the Layout toolbar.

The Size and Position Tab

The “Size and Position” tab will define the fixed size and position in the layout of the legend. Size will adjust when the graphical legend is resized unless the “Fixed Frame” box it ticked in the “Layout” tab. The position will define where the defined anchor point of the legend sits in the layout using map inches. These numbers will change when the graphical legend is dragged around the layout.

Converting Legends to Graphics

One option in ArcMap is the ability to convert elements to graphics, meaning that object becomes a non-dynamic graphical object. If change are made to the layers in the Table of Contents, those changes will not be reflected in the legend. While this option is handy for things like creating non-traditional legends, if there is a means of making an adjustments in the legend options, that is how it should be done. Converting to graphics can be useful, but definitely more of a challenge for the new user. Get good at using the legend options, then use the convert to graphics option for everything else.

Legends can be converted to graphics by right clicking on the legend itself and select “Convert to Graphics”. The graphic can then be ungrouped and each element moved, deleted, or copied. After they are in place, the elements can be then regrouped.

Right click and select “Convert to Graphics”The legend can then be ungrouped.
After the elements are placed, they can be the regrouped