Marketers frequently place maps on websites and other communications materials to indicate the locations of businesses and events. That’s a good thing for the visual learners in the crowd.

But sometimes those same marketers shoot themselves in the foot by ignoring the conventions that have become common in mapmaking. For example, professional mapmakers indicate bodies of water, such as rivers or lakes, in blue (and usually a light blue). Over the centuries, we’ve become conditioned to associate water with the color blue. It’s what our brains expect to see. Using a different color rattles the brain and interferes with understanding.

Similarly, those of us in the Northern Hemisphere are accustomed to maps in which north is at the top, south at the bottom, west at left, and east at right — and most mapmakers (and online map and GPS sources) do exactly that. Some who design marketing pieces are either unaware of this convention (or just dislike rules of any sort), so they twist their maps so one of the other directions is at the top. But all that does is confuse users and make the map less useful.

Map symbols have also become standardized over the years. Since the Interstate system was started, Interstate highways have been designated by a rounded shield that’s mostly blue, with a red top that has three points. Other U.S. highways are represented by a different type of shield and normally presented in black and white. Each state has its own approach for state highways. Because those symbols have become so familiar, it makes sense to use them when creating maps. Here again, though, some marketers seem to believe one symbol is the same as another, so they interchange them (and yes, that pun was fully intended).

Conventions like map colors, symbols, and alignment exist because they’re traditional and familiar. They work well. So if you’re going to be kind enough to customers to give them a map to your location, also be kind enough to create the map using the symbols and styles they’ll recognize.