Polygon Background

Cartography · Graphic Backgrounds · ribbon tool with its own window · by Jeff Jenness

Works at every ArcGIS Pro license level

Summary

Draws a polygon that follows the actual shape of the selected graphic or layout elements, then groups the polygon and the selection together with the polygon underneath. Where the circle and rectangle tools work from the bounding box of the selection, this one traces each element, optionally grows or shrinks the trace by a buffer, and merges the results into one background. It makes halos, glows and close-fitting panels around irregular shapes.

The words Here be Dragons! in an ornate typeface, curving across a tinted relief map on a pale yellow, partly transparent background that follows the curve of the lettering, with a dark outline and a soft shadow along its lower right edge — A polygon background around curved text. The background follows the shape of the lettering, where a rectangle would have boxed in a good deal of empty map.

How it works

Each selected element is traced, either from the geometry it is built from or from its shape as drawn. Each trace is buffered by the buffer size, and the buffered shapes are merged into a single polygon, which is drawn with the chosen symbol and grouped behind the selection. Elements that are far apart give a background in several separate parts, one around each; elements close enough for their buffers to touch are joined.

An element that has been rotated is traced in its rotated position.

A point or a line has no area, so by itself it cannot make a polygon. When a selected shape is a point or a line, give a buffer size greater than zero and the background becomes the buffer around it. The tool says so if the buffer is missing.

What to select first

The tool works on selected elements: graphics in a map's graphics layer, or elements on a layout (text, pictures, legends, north arrows, scale bars, map frames and so on). It does not work on features in a dataset. Select one element or several, then click the tool. If nothing is selected, the tool says so and stops.

The Cartography Tools gallery open on the ribbon, with the Polygon button, in the Graphic Backgrounds row, outlined in blue — Where to find it: **Polygon** is in the *Graphic Backgrounds* row of the *Cartography Tools* gallery, in the Cartography group of the *Wildlife and Forestry* tab.

On a map, the selected graphics must all be in one graphics layer. A selection that spans two graphics layers is turned away with a message.
If a selected element already belongs to a group, the whole group comes along. The tool never pulls a group apart.

A tour of the dialog

If we buffer a text graphic, we can get a nice buffer and shadow:

The Polygon Background dialog over a tinted relief map: a graphic name of Dragons!, a pale yellow swatch, fill transparency 50, outline transparency 0, Fit polygon to set to The symbolized shape, a buffer size of 0.21 inches, Remove any holes in polygon checked, and the Drop shadow box checked with black, opacity 60 percent, angle 135 degrees, distance 5 points, spread 0, size 5 points and 10 layers. At the lower left of the map, the curved text Here be Dragons! sits on the resulting pale yellow background with its soft shadow — The dialog and its result. The text is traced by its *symbolized shape* and buffered by 0.21 inches, which gives the scalloped outline that follows each word. *Remove any holes in polygon* fills the gaps the buffer leaves inside and between the letters. The fill is pale yellow at 50% transparency, and the drop shadow uses the starting settings.

Control	Explanation
Graphic name	Optional. The name given to the new polygon. On a layout it is the name shown in the Contents pane; on a map, graphics are not listed there, and the name shows in the Element pane when the graphic is selected. The new group is named after it, with “Group” added. Left blank, the polygon gets ArcGIS Pro's default name and the group is named Graphic Polygon Group.
Symbology / Design symbology…	Opens ArcGIS Pro's own Format Polygon Symbol editor, gallery included, so the background can carry any polygon symbol: a solid fill, a gradient, a hatch, any outline. The swatch beside the button previews the chosen symbol before transparency is applied. The starting symbol is a pale yellow fill. The Format Polygon Symbol editor, with its Gallery of ready-made symbols on one tab and the symbol's layers on the other. Here, a 1-point black outline over a gradient fill.
Fill transparency (%)	0 to 100. Applies to the interior fill only. Gradient fills are made transparent evenly across the whole gradient.
Outline transparency (%)	0 to 100. Applies to the outline only, so a see-through fill can keep a solid border, or the reverse.
Fit polygon to	The element's geometry uses the shape the element is built from: the vertices of a drawn polygon or line, with no allowance for the thickness of its symbol. The symbolized shape uses the element as it is drawn, symbol widths included, so a thick outline or a large marker is fully covered. For elements that have no geometry of their own to trace (text, legends, pictures, map frames and the like), both choices use the element's drawn bounds.
Buffer size	Optional. 0 traces the shape exactly. Positive values expand it and negative values shrink it. On a map the buffer is in the units of the map's coordinate system, named beside the box. On a layout choose millimeters, centimeters, inches or points.
Remove any holes in polygon	Fills every interior hole so the background is solid. Holes can come from the elements themselves (a ring-shaped graphic) or from the merging, where buffered shapes surround a gap.

Click OK and the polygon is drawn. Cancel closes the dialog and changes nothing.

Drop shadow

Check Drop shadow and the tool draws a soft shadow beneath the polygon, the kind that makes a panel look as if it is floating a little above the map. The controls follow the drop shadow settings in Adobe Photoshop, so they will be familiar if you have used those.

A shadow by itself. The background does not have to be visible. We can also create just the shadowing effect around lines, by setting a very small buffer and making the polygon totally transparent. For example, this arrow showing where the dragons might be, shadowed so it appears to float above the map:

The Polygon Background dialog over the same relief map: a graphic name of Just Shadow Lines, fill transparency 100, outline transparency 100, Fit polygon to set to The element's geometry, a buffer size of 0.01 inches, and the Drop shadow box checked with the same settings as before. On the map a thick hand-drawn black arrow curves from the Here be Dragons! label up to a valley, with a soft shadow offset to its lower right — A shadow with no visible background. The arrow is a line graphic, traced by *the element's geometry* and buffered by only 0.01 inches, with the fill and the outline both 100% transparent. Nothing of the polygon shows. Only its drop shadow does, and the arrow appears to float above the map.

Control	Explanation
Color	The color of the shadow. Black or a dark gray is usual.
Opacity	How dark the shadow is at its darkest, from 0 to 100%.
Angle	The direction the light comes from. The shadow falls on the opposite side. Click or drag on the dial to point it at the light, or type the angle in degrees, measured counterclockwise from east: 90 is light from the top, and 135 is light from the upper left, the usual choice on a map.
Distance	How far the shadow is shifted away from the light. A larger distance makes the polygon appear to float higher. 0 leaves the shadow directly underneath, showing evenly on all sides as a soft glow.
Spread	How much of the soft edge is made solid. 0 gives the softest edge. 100 gives a hard-edged shadow.
Size	The width of the soft edge. 0 gives a hard edge with no softening at all.
Layers	The number of pieces the soft edge is built from, 1 to 60. More layers give a smoother edge.

Distance and Size are in points on a layout, and in the units of the map's coordinate system on a map.

How the shadow is made. ArcGIS Pro graphics cannot be blurred, so the soft edge is built from a stack of plain polygons. Each is a copy of the polygon's outline, shifted away from the light, with a solid fill that is mostly transparent. The copies are made in a graded series of sizes, the largest a little bigger than the outline and the smallest a little smaller. Where more of them overlap, the shadow is darker, so it fades smoothly from nothing at its outer edge to the full opacity inside. The opacity of each copy is worked out so that the darkest part is exactly the opacity you asked for, however many layers you choose.

The shape of the polygon itself is cut out of every layer. The shadow therefore lies around the background and never underneath it, and a partly transparent background keeps its own color and is not darkened by its shadow.

The shadow's layers are ordinary polygon graphics. They are grouped together, and that group sits below the polygon inside the new group.

What you get

One new polygon graphic, placed behind the selected elements, and one new group that holds the polygon and everything that was selected, along with the drop shadow if one was asked for. Because they are grouped, the background and its contents move, resize and copy together.

Layouts give you more room to work ArcGIS Pro is much more flexible with graphic elements on a layout than on a map. On a layout, the Contents pane lists every element. Expand the group there and you can select the polygon by itself, edit it, hide it and show it again. On a map, the Contents pane shows only the graphics layer and does not list the graphics inside it. A group can only be selected as a whole, so its members cannot be picked out one at a time. To change the polygon on a map, select the group and ungroup it (right-click the group, or use Arrange on the Graphics tab), make the change, then select the pieces and group them again. Be careful with the Visible check box in the Element pane too: on a map, a graphic that has been made invisible can no longer be clicked, and with no list to pick it from there is no way to select it again and turn it back on.

The polygon is an ordinary ArcGIS Pro graphic. Nothing about it is special once it is drawn, so it can be edited by hand like any other: select it and use the Element pane to change its symbol, its size, its position or its name.

Nothing else is altered. The selected elements keep their own symbols, sizes and positions.

The tool remembers your choices

After a successful run, the symbol and every setting in the dialog are stored with the project, so the next background starts where the last one left off and a set of backgrounds comes out matching. Each of the four Graphic Background tools keeps its own settings. The graphic name is never remembered. The settings are saved when the project is saved.

Messages you may see

Message	What to do
A selected element's shape is a point or line…	Enter a buffer size greater than zero.
The buffered shape is empty…	A negative buffer has shrunk the shape away to nothing. Use a smaller negative buffer, or a positive one.

Recommended citation

Jenness, J. 2026. Polygon Background. Wildlife and Forestry Tools add-in for ArcGIS Pro, v. 1.113.62.1 (October 2026). Jenness Enterprises. Available at: https://github.com/JeffJenness/Wildlife_Tools.

Credits

By Jeff Jenness, Jenness Enterprises (www.jennessent.com).

Licensing information

Works at every ArcGIS Pro license level (Basic, Standard, Advanced). No extension licenses are required.

Circle Background — a circle behind the selection, the natural fit for a compass rose or any round element.
Rectangle Background — a rectangle behind the selection, with square or rounded corners.
Minimum Convex Polygon Background — the tightest convex outline around the selected elements.
Create Shadow Polygons — a soft shadow of fading rings around the polygons of a feature class, where these tools shadow graphics.