ArcGIS Pro

Mapping with purpose

You have data, but that’s not enough to make a map. You also need a purpose. There’s no point in making a map unless you have something to say.

Making a map means making many decisions. Making decisions without guidance is hard. Making decisions toward a goal is easier. Consider these common questions:

Until you’ve decided on your map’s purpose, answering these questions will remain difficult.

Map of blueberry crops in Canada

I made the map above without knowing what I wanted to say. My lack of intent resulted in an uninteresting map.

That’s ok! Experimenting with symbology, making charts, and exploring the attribute table are all important methods that you should use to become familiar with your data. Never assume that you already know what your data says, or what you want to say with it. Making different maps is one method for arriving at your intention.

But it’s important to distinguish between the maps you make for yourself—to help you explore your data—and the maps you make to share with others. The maps you make to share should be purposeful.

If I stopped my experimentation here and called the map complete, what messages would be communicated to the reader?

Your map will always convey some message. It’s important to assess if it’s the message you intended.

You can communicate your intended message more clearly if you design the map with it in mind. If the messages listed above were intentional, rather than accidental, I might arrive at this map:

Map of blueberry crops on the west and east coasts of Canada

I made the map above knowing what I wanted to say. This goal led to the following decisions:

Consider a different map intention: to determine which region grows more blueberries, Quebec or the Maritime provinces.

Map of blueberry farming in Quebec and the Maritimes

This intention is narrower and more focused. It results in a more effective and interesting map.

With the exceptions of basemap and projection, every decision I made for this map differs from the previous two maps because I was guided by a different goal.

Consider one more intention: to show that blueberries are the dominant berry crop grown in Canada.

Map of berry crops in Canada, with stacked bar charts

For this map, comparing blueberries to other berry crops was important. Symbolizing by charts allowed me to do that.

Should you even make a map? If you find that you’re fighting with your map to make it say what you want it to say, consider other methods of presenting your data. In the example above, do I need to show the geography? Could a single stacked bar chart convey my message more clearly?

Stacked bar chart of berry crops in Canada
Sometimes the best map isn't a map

In all of these examples, shifting the intention resulted in different choices and different maps. What is the intention of your map? Why are you making it? What do you want it to say?

You can phrase it as a goal:

You can phrase it as a statement:

You can phrase it as a question:

Make sure that your map doesn’t just ask the question—it should also answer it.

Map of saskatoon berries in Alberta and Saskatchewan
Don't be afraid to state your intention outright. Consider making it the title.

Gone are the days when maps merely stored information. We have computers for that now. A good map has something to say.

You can download MappingWithPurpose.ppkx to view all of the maps shown in this article and see how they were constructed in ArcGIS Pro. The primary dataset used in these maps is the Census of Agriculture 2016 – Crops layer from ArcGIS Living Atlas of the World, sourced from the Government of Canada 2016 Census of Agriculture.

You can find more cartography tutorials on the Introduction to Cartography page.

About the author

Heather is a cartographer and artist. She creates resources for the tutorial gallery.

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