Figure 1.
DOI: 10.14714/CP104.1949
© by the author(s). This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License. To view a copy of this license, visit http://creativecommons.org/licenses/by-nc-nd/4.0.
Vicky Johnson-Dahl (she/her) | vicky@vickyjohnsondahl.com
This article is adapted from the author’s 2023 Practical Cartography Day presentation.
Locator maps play a small, underappreciated role in cartography. These little maps offer viewers quick, broad geographical context that situates the main map within its surroundings and helps the user quickly grasp where the focus area lies within a larger region. In this article, we’ll make some small changes to improve the locator on a simple map of a trail in Orchard Park, NY (Figure 1).
Figure 1.
While the concept of a locator map is straightforward, the choices a cartographer makes in designing it can significantly impact its effectiveness. A well-crafted locator map enhances the primary map by adding value without overwhelming or distracting from it. We’ll examine key considerations in designing a locator map, from framing and placement to labeling and scale, ensuring that your locator map is both functional and visually engaging.
The best part about these tips: they’re all pretty quick! At least in my experience, the locator map is one of the last things you do to complete a map layout, almost as an afterthought. So when you’re working on your locator map . . .
Adding a drop shadow is the single easiest way to make your locator map pop (Figure 2). It’s just a flat box shifted slightly down and to the side. It only takes a second to add, and gives the impression that your locator map is floating above the main map, adding a little visual dimension and interest. I like a box for this, but a blurred, drop shadow effect is nice, too. It doesn’t affect the content of either map, but just makes the locator look a little sharper. A drop shadow only takes seconds to implement. Simple, quick, and effective.
Figure 2.
Your locator map doesn’t have to sit inside of a box. If your locator is based on an area (a country, for example, or as shown in Figure 3, a park), you don’t need to show what’s outside that area, you can just show the area polygon itself. Note that you may have to change some aspects of the map in order to keep it from blending in with the map underneath or being mistaken as an element on the main map.
Figure 3.
The locator map doesn’t have to be shoved into the corner. Use the space available to you, and fit the locator on the page where you have open space. This is especially useful when your allotted page area needs to hold other information, like explanatory text or this admittedly underwhelming photo (Figure 4).
Figure 4.
This also comes in handy where you have something irrelevant and distracting. If it’s something likely to invite problems outside of your content—like a nearby disputed border irrelevant to your subject area—the locator map can give you literal cover.
Make sure your inset map fits in with the rest of the page layout (Figure 5). This works especially well when you’re working with strict limitations, map standards, or design guidelines—it’s a way you can add personality while keeping the maps thematically consistent. Here, the inset background shape mirrors that of the main map with rounded corners.
Figure 5.
Text is precious on a map. It also takes up a lot of space—I have a theory that the longest names are given to the smallest polygons and I have some iffy math to back that up—but in a locator, which is a constrained space, you have to make tough calls. What I am suggesting here is: leave as many labels off as possible. Figure 1 has the park and street names, but the outline-free versions, like Figure 4, work with even less.
How much do you really need to show? What is the minimum necessary so the viewer can orient themselves? What is the maximum that is still sensible for the context? Work in that middle space to identify a scale that does the most for you and your audience. The locator in Figure 6 shows the county, for example, instead of just the park.
Figure 6.
You’ll note that none of these locator maps have a north arrow or scale bar. Why would it? It’s just for reference.
Most of these tips are about doing less. Once you’ve done less, you’ve removed the extraneous clutter and your locator map can be more useful. What other contextual information can you add to the locator that broadens the map’s overall utility? For example, the locator in Figure 7 shows where the trail is in Western New York, and how far it is from another notable waterfall in the area.
Figure 7.
This one goes hand in hand with the previous tip: keep an eye on that other stuff. Remember that the locator map is small (Figure 8). You can save yourself a lot of time by viewing the map at actual size, or printing it out. The text on locator maps can get pretty small, so you want to make sure that you keep it legible. It can be a nasty surprise right at the end when you think you’ve finished your map, and you then have to go back and rearrange and redesign so that the locator is usable.
Figure 8.
You made a locator map you like? GREAT. You just saved future you a bunch of time. When you’re making a locator map, keep the foundational document, and keep the layers clean and labeled so you can paste that on your next map. You can adjust the content, the extent indicator, and the aesthetics, but you should never have to recreate the structure. When you find yourself doing difficult work on the fly, save yourself precious minutes. Copy and paste.
Hopefully these ten tips—just one at a time, or a few in combination—give you some ideas for your next locator map. A couple of easy little tweaks can make a big difference!