ESRI Mapping Center - Maps: European Energy

Example of a customized proportional symbol legend

What: We created the above legend using graphics instead of creating legend element, which could not support the precise style we wanted for this legend. Why: A graduated symbol legend should, if possible, relate very directly to the map. Thus, the way the symbols superimpose and the sizes of the symbols is important. To aid readers of this map in interpretting the size of the graduated symbols, the legend depicts the largest, the smallest, and a representative middle values. In this map, we felt including the graph at the lower right also provides the values for the symbols, which helps ensure map reading errors are minimized.

How: On the map the smaller orbs were superimposed in front of the large orbs by converting the layer to graphics. Those graphics are stored in annotation groups in the data frame; this strategy created one big advantage for creating this legend: the graphics we needed for the legend could be selected in the map, copied, and then pasted in the layout.

To create this graphic legend, you should be working in ArcMap in layout view, and then follow these steps

First, you'll need to focus the data frame that contains the graphics. You can do that by double-clicking it.
You'll need to open the attribute table for the layer that was used to create the graphics and sort the data field to find the place with the lowest and highest values.
1. Select and copy the graphic representing the highest value.
2. Click anywhere in the layout outside of the focused data frame to unfocus the data frame.
3. Choose paste from the edit menu. This will paste the graphic into the layout, and you can now move it to the general location where you will build your legend
4. Repeat 2a-2c for the lowest value, and for a middling value.
Arrange the pasted graphics of your symbols in fashion like above, or as your map’s design requies. .

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Use the graphics toolbar, which contains tools for front to back ordering to superimpose the symbols.
Add text for legend title, explanation of units of measurement, and labels for each of the symbols shown. It is important to label the symbols not only with their data value, but also with the place they represent-making it easy to find on the map and then a basis for comparison with other symbols on the map.

For more about designing legends for proportional and graduated symbol legends see page 177 in Designing Better Maps.

Designing the spherical symbols? posted by Vincent Launstorfer on Jan 7 2008 9:29AM

The methodology to make the legend is interesting, but I would have liked to understand how you made these spherical symbols at first instance. How did you make them from scratch in ArcMap?

Making the picture marker symbols posted by Charlie Frye on Jan 7 2008 1:47PM

To create the symbol's artwork, we used Adobe Illustrator (CS2, I think) and a circular blend. The result was exported to .emf (Enhanced Metafile), and was used as the basis for a Picture Marker symbol. We also did the drop-shadows as separate .emf files so they could be shown with some transparency.

"Customized" proportional symbol legend posted by Timothy Tresohlavy on Mar 16 2010 7:35PM

Now, wait a minute. You created icons in Adobe Illustrator, and not ArcMap, to display your geographical dataset ... two sets of them ... then you had to manually create a legend ... does anyone else see the problem with this approach?

There are many options posted by Aileen Buckley on Mar 17 2010 8:20AM

Actually, you can make your picture marker symbols in a variety of different ways -- you just need to make sure that the picture marker symbol is in .bmp or .emf format. We give you a lot of fexibility in this. How you make them is up to you -- use whatever is easiest but gets the job done for you. You could even use ClipArt images! You could do something like this in Arc as well, but you would not get exactly the same illumination effect.

Leveraging resources posted by MappingCenter Team on Mar 17 2010 10:23AM

The point, in responding to Timothy's question, is that ArcMap is not an illustration graphics software package, and therefore does not have all the graphical display features you might want to create a distinctive symbol. Being able to import artwork as a symbol is nice option to have (versus not being able to).

There, of course, is a broader debate about when or whether to leverage the automation possible in GIS when creating a more illustrative style map that could be done in a graphics package. That debate does not purely come down to functionality, but also includes the acquired skillsets to leverage either or both environments effectively. It's always more difficult for a deeply experienced expert of one kind of software to quickly leverage another kind of software, and the more complicated the software the more frustrating--so you might imagine that the intersection of GIS and graphics software is a bit of a crucible because nobody has the time or wherewithal to be an expert at two things simultaneously (the concept is an oxymoron).

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