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Five tips for creating effective symbols and maps in ArcGIS

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Author Melanie Meeking

There are so many resources out there to help us make better maps. The sheer volume can feel overwhelming at times! Read on for a compilation of Esri Canada certified ArcGIS instructor Melanie Meeking’s favourite links to help make some sense of it all.

A lot of decisions need to be made when you’re building a map, whether it’s for print or the web. Maps are meant to communicate a message, and one of the most important things we do when creating a map is make decisions about symbology. You might choose to vary the size, shape or colour of your symbols to distinguish between feature types or values. The symbols you choose need to be clear and help share your message, but it’s even better when your maps are also nice to look at.

We combine science with art when we make maps. With ArcGIS we can leverage advanced symbology techniques to create interesting, authoritative visualizations. Are you looking to jazz up your maps with some effective and exciting symbology techniques? Here are five ways you can do that.

Create a visual hierarchy

Maps typically have two different kinds of layers: base maps and operational layers. The base map provides reference information for the map reader, whereas the operational layers show the data that is actually the point of the map. As a mapmaker, we want to draw attention to the operational layers in the map—these are the features that are communicating the map’s purpose. We can use symbology to situate each layer in a visual hierarchy to accomplish this—drawing more attention to the layers at the top of the hierarchy by using visual techniques to draw the reader’s eye. This blog post describes visual hierarchy in more detail.

Three maps of Halifax, Nova Scotia, specifically the peninsula, which are distinguished from one another by their different symbology. L-R: a map of Halifax that uses the colour yellow to prominently highlight proposed conservation districts; a map of Halifax that emphasizes buildings by displaying them in an intense shade of brown; a map of Halifax that emphasizes heritage properties by representing them with bright red polygons offset against the basemap with a drop shadow.

Clearly display overlapping polygons

John Nelson always has great ideas for symbolizing data. I highly recommend browsing through his blog posts for some very cool ideas on presenting your geographic data. One example to get you interested: it can be challenging to effectively present overlapping polygons in a way that is clear to the reader. In this blog post, John Nelson presents a number of symbology options for this common situation—check it out. Don’t forget to check out the rest of his blog as well for other great mapmaking and symbology techniques!

Map detail of an unidentified area, showing two large, overlapping polygons over an area of what appears to be desert adjacent to parcels of farmland. One polygon, in the centre of the map and slightly to the right, is coloured blue. The second polygon is yellow, and is situated in the centre of the map and slightly down and to the left. In the areas where the two polygons overlap, the map is hatched yellow and blue to indicate the overlap without completely blocking view of the basemap underneath.

Use feature blend and layer blend

One of the techniques featured in the abovementioned blog post by John Nelson is feature blend. Blend modes have been around for a while (introduced in ArcGIS Pro 2.7), but I think they’re worth their own bullet point. Blending allows you to do just that—blend the features in your layer together (feature blend) or blend those features with the features in the layer underneath them (layer blend). This can achieve some interesting visual effects that will help communicate your message or even just make things look neat. If you’re not already familiar with the layer and feature blend options, check out this video and this blog post for more details.

Three maps are shown, two on the left and one on the right. The idea of this image is to show that colourful elements of the two maps on the left can be multiplied together using Blend Modes in ArcGIS Pro to create a third map that shows both sets of elements. The first map, in the top left, is a world map called “vintage shaded relief”, which shows a brightly coloured topography. It’s labelled “Top layer” and is joined to the second map, in the bottom left, with a plus sign indicating they’re being combined. The second map is called the “firefly world imagery layer” and features a dark ocean with desaturated topography, intended to be overlaid with brighter elements for analysis. The third map, which combines the two previous maps, has brightly coloured landmasses with vintage hillshade surrounded by a dark ocean.

Incorporate accessibility features

It can be a lot of fun to build interesting symbols for our maps. But before we get too carried away, it’s a good idea to consider how accessible your map is. There are a number of tools and strategies that can be used to help create accessible maps—check out this post with all the details.

A screenshot taken in ArcGIS Pro, which simply shows the Color Vision Simulator menu, with options to simulate deuteranopia (green-blind vision), protanopia (red-blind vision) and tritanopia (blue-blind vision). The deuteranopia option is currently highlighted.

Build a concise but descriptive legend

Once we’ve got everything symbolized, we need to communicate with our audience—what do all those symbols mean? Configuring legends can be finicky work, but it’s well worth the time to build a concise but descriptive legend. Check out this series of videos on tidy legends, as well as these tips and tricks for ideas on building great legends. 

For more tips and tricks on creating visualizations in ArcGIS, come check out our two-day day instructor-led class on the topic: Mapping and Visualizing Data in ArcGIS. In the class, we chat about symbology as well as labels, and get into details on creating layouts for print as well as web maps. We even talk about working with charts in ArcGIS, working with 3D and creating animations.

Want to stay informed about all the latest training opportunities at Esri Canada? Visit Esri Canada’s Communication Preference Centre and select the “Training” checkbox to get a monthly roundup straight to your inbox.

About the Author

Melanie is an Instructor on the National Training Team at Esri Canada. She has been working with GIS for over 15 years and currently teaches courses on ArcGIS Pro and ArcGIS Online.

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