Guide to Editing Map Legends

Remember that your map needs a legend. Map legends explain map symbols and are crucial to the communication of a map’s message. Legends in ArcGIS Pro are very powerful, but they can also be tricky. There are many different options available. It can be hard to know where to start. Effective legends are created with careful consideration of labels and text, classes, colours, as well as map and general design principles. This document provides some basic principles of legends as well as how to use ArcGIS Pro tools to create and edit legends. 

Figure 1 shows a finished map with an edited legend above and figure 2 shows a default legend which has not been modified respectively. My experience has been that once an ArcGIS Pro user adds a legend, what the map-maker (you and me) wants to change is more clear. This document will go through how to edit this default legend (Figure 2) as well as introduce the various options of legend editing. 

• Legend insertion and editing is done after a Layout is added in Pro. As described elsewhere, the Layout view is where we prepare our map for display and communication. In the Layout tab, after we have set the "page size and orientation," click Insert in the ribbon, and select Map Frame. This is how we specify which of our map tabs (we might have more than one) are going to be included in the layout, aka map (we might include more than one).

• Once Layout has a geographic layer (map) added to it, there is a lot we can do. As regards Legends, under Map Surrounds group select Legend, and click and drag your cursor on the map to specify the legend's location on the layout.
• Depending on the type of map (single, side-by-side, pair, small multiples, etc.) you are making, you might add more than one map frame to the layout and therefore more than one layer of data from the Contents pane. 
• Adding selected items: When you create a legend for your map, you don’t have to include all the layers in the map. You have to select specific layers in the Contents pane to be added to your legend, only the selected layers are added to the legend. If you forgot to select a layer, no worries, you can still add it after the legend has been created.

Once you have inserted the legend into your map, it will look something like the one below: with a lot of values, which may not be meaningful to your readers, or for the purpose for which the map was made.  

When you select the Legend either in the Contents pane or on your map. The Legend is activated in the ribbon. Clicking on Format will give you the opportunity to format some basic things on your map legend, including the fonts among others. (See figure 5) 

There are several ways that this default legend can be improved without directly editing the legend itself and instead editting in the Symbology pane.  

• Open the symbology for the layer that corresponds to the legend using the Contents pane. Here you can edit the labels and class divisions. The classification should accurately reflect the information and the labels for the classes should be clear and intuitive (whole numbers are best for most maps).  
• In the Contents pane, right-click on the layer and select Symbology. By clicking the Advanced symbol options (the fifth item at the top) in the Symbology pane and expanding the Format labels (Figure 6 (1)) you can specify what kind of number (Category) the labels are (numeric, percentage, rage, direction, etc.) 
• In this pane, under Rounding, you can decrease the number of decimal places or significant digits. Try playing with this option to reduce the values in your legend.
• In the Symbology pane under Primary symbology, you can slow click the labels (classes) to change the divisions and edit with words like “more than” and “less than” (Figure 6(2)). Note: However, you have to be careful with these since the default for ArcGIS Pro is to use ≤. Once you have made changes click in another box for the symbology to reload. The changes will be reflected in the legend.

Note: The symbology of the layer is always connected to the legend. Updating the symbology in the map automatically updates the legend item. Also, deleting a layer in the map always deletes the corresponding legend item.

A map legend is made up of legend items. We can set properties at either the legend or legend items. In the Element pane, you have the opportunity to edit the legend and legend items (individual layers in the legend).

• The legend contains properties that apply to the entire legend element, like the fitting strategy, title, word wrapping, and background. 
• We set the properties at the legend level. To do this, select the Legend in the Contents pane, right click and choose Properties to open the Element pane. There are four tabs in the Legend Element pane: Options, Legend Arrangement Options, Display, and Placement tabs. This section will outline the various options and tools in each tab.
• These are from left to right:

1. Options tab: This is the first of the four tabs. (You will know the name by hovering your cursor and briefly pausing on an item). Turn on or off the legend title and adjust the title text. Here you can insert the title for your legend, among other things.

Adding Legend title

In the Element pane, you can turn on and off the legend title. A general rule is that the title of your legend should never be “Legend;" it should communicate something about the map and what the symbols represent without duplicating the map title. You can also set the font and text settings (character spacing, font, size, colour etc.) for your legend title by clicking Text Symbol or in the ribbon. It is possible to make your legend title appear on more than one line by pressing the enter key where you want the new line to begin.

Synchronize with the map

• Remember to ensure that you check the Synchronize with map options at the legend level to keep the map layers and legend items in sync. There are four sync options. They are particularly useful if your map isn’t quite finished when you start building the legend.
• Layer visibility: Any time you turn a layer off in the map, the corresponding legend item will also be turned off.
• Layer order:  Sets the legend item order to match the layer order in the map.
• New layer: Adds a new legend item any time a layer gets added to the map.
• Reference scale: Scales the symbology based on the map’s set reference scale.

2.    Legend Arrangement Options tab: This is the second of the four items at the top of the Element pane. Contains fitting strategy, word wrapping, and spacing properties.

• As layers are added, removed, or the legend is resized your legend grows and shrinks. How the legend items get arranged when the legend changes size is determined by the Fitting strategy. In ArcGIS Pro there are four main fitting strategies that we can use 

1. Adjust font size: Shrink the font until all the legend items fit. You can set minimum font size to make sure your font doesn’t get too small for your readers to read. If the legend items can’t fit in that font size, they are dropped. While the font size shrinks if needed, it never grows past the font size set for the legend.
2. Adjust columns: This fitting strategy adds more columns until all the legend items fit.

Note: The size of the text for the legend doesn’t change, but more columns are added. If there isn’t enough room in the legend for more columns, items are dropped.

1. Adjust columns and font sizes: Unlike the Adjust columns, this fitting strategy shrinks the font AND add more columns until the legend items fit. Similar to adjust the font size, the text can get smaller than the set font size if needed, but it never grows larger. 
2. Adjust frame: The legend becomes the size needed to fit all the legend items. You can’t resize the legend. Note: When you are working with an ArcGIS Pro project that has a legend that cannot be resized the fitting strategy is perhaps set to adjust frame.

• Also, in this tab there are spacing options. This is where you can set the font properties and character spacing for the classes by clicking the symbol button. You can also set the number of columns. You can change the gap spacing between legend. You can change the defaults. There are many possible options for using gap settings.
• Note: when experimenting with gap settings it is helpful to keep in mind the original gap values so that you can revert to the original settings if you like.  
• Word wrapping is useful if you need to fit your legend into a narrow area in the layout and have longer class labels. 

3.    Display tab: In this tab you can set Borders, Background, and Shadow properties.  

• If you choose to use a border you will likely need to set a gap (x and y) to create enough space between your border and your legend text. Rounding can also be set.  
• If you choose to use a background fill you need to set the same gaps and rounding as your border so that they line up.  
• Drop shadow creates a shadow behind your legend and allows you to set the x and y offset of the shadow.  
• Note: You can play with these options. Remember to set the same gaps for the border and the background if you are including both in your legend.

4.    Placement tab: This tab will enable you to work on Size and Position (Figure 11)

• In this tab, you can set a specific position where you want your legend to appear in your layout as well as the width and height (resizing and alignment can also be done manually in the layout view using grid guides)

Items in the legend have properties that can be different for each layer, including the patch height and width, the label text size, feature display options, and change indent value. If all the classes in the layer are included or only the ones visible in the map extent. You can set properties for each item individually or multiple items at once. In the Contents pane right click on any of the Legend Item and select properties. This will open the Element pane for the item. 

• If you select an item or items, the Element pane updates to show the properties of the item or items. In Figure 12, the Element pane for Toronto is opened.
• Under Show in the Element pane, you can clean up your legend by turning “on” and “off” some elements in the legend. For example, if you have a layer name appearing in the legend, you can turn it off to remove it from the legend. The options you can change here include Group Layer Names, Layer Names, Headings, Labels, and Descriptions. You can play with these options and check how your legend changes.
•  Arrangement: This shows how you want the layer to be displayed. Clicking in the box will give you a dropdown list to choose from. You can change these settings to see which arrangement works better for you.
• Sizing: It gives you the option to increase the width and height of the patch (In this example, it is the coloured boxes in the legend). You can try this by increasing the width and height of the patch in your legend to see how it works. Remember to make your patch readable and not too big.

There are other things that can be edited in the Feature Display Options and Indents

Note that you can edit the text and properties of the text of the Legend item by selecting Text Symbol in the Element pane. You can explore some of these.

You can also edit Group Layer Names, Layer Names, Headings, Labels, and Descriptions. Check figure 13.

• When you have inserted a legend, you can change the order of the items in the legend to suit your purpose at any time. In the Contents pane, select the item you want to move from the legend tap and then drag it up or down on the list to the order you want. In this particular example, there is a “no data” layer that should appear below the other symbols on the legend. This can be accomplished by selecting “no data” and dragging it to the bottom of the list in the legend. 

Once you have experimented and selected all of the settings through the Element pane, additional editing can be done outside of the legend properties. For example, in the Insert tab, you can insert text boxes with information about the classification, units of analysis etc. You can resize and move the legend in the layout view using your mouse. You can also right click the legend and use the align tool if you want it to be aligned to a specific border or element of your map.  

Another option, if you want to do specific editing, is to “convert to graphics." This dissociates the legend from the layers in your table of contents. This allows you to specifically edit the symbols and labels independently from each other and resize the frame and border independently from the legend entries. Some examples where converting to graphics may be useful could be if you run into colour contrast issues between your map and legend, if you want your legend symbols to have outlines but not your map symbols, or if you want to reposition individual symbols or text within the legend. The gap at the bottom of the legend in Figure 15 that makes room for the text boxes was created by converting to graphics.  

• To convert to graphics right click on your legend and click convert to graphics and then continue to right click and choose ungroup until you have separated the legend elements (Figure 15).
• Edit specific legend elements by right clicking and opening properties and symbology.  
• You can group the legend elements back together by selecting them, right clicking, and choosing group so that you can move the entire legend around easily. 

Important Note: You should only convert to graphics as a last step in the map creation. By converting to graphics you dissociate the legend from the layers in the table of contents and any subsequent changes you make in layer symbology will not be reflected in the legend. For example, if you wanted to change your map’s colours you would have to manually reset the legend colours.  

 https://pro.arcgis.com/en/pro-app/latest/help/layouts/work-with-a-legend.htm#:~:text=In%20the%20Element%20pane%2C%20select,properties%20you%20want%20to%20change.&text=Turn%20on%20or%20off%20the,and%20adjust%20the%20title%20text .

 https://www.esri.com/arcgis-blog/products/arcgis-pro/mapping/tips-and-tricks-for-working-with-legends-in-arcgs-pro/ 

 https://pro.arcgis.com/en/pro-app/latest/help/layouts/work-with-legend-items.htm