Debate: Does the Mercator projection actually make sense for navigation apps?

So I was looking at a map of Greenland on Google Maps the other day and realized it looks nearly as big as Africa. We all know that's not true but it made me wonder something. For driving directions or city maps, does it really matter if the projection distorts size? I get that it's terrible for world maps showing country sizes but for turn by turn stuff around town it seems fine. On the other hand, I saw a post where someone used a Peters projection for a road trip and the angles were all weird and they got lost. So which side is right? Is Mercator good enough for local navigation or should apps switch to something else for accuracy? Has anyone here actually tried using a different projection for a real trip and noticed a difference?

2 comments

2 Comments

wesley_hart5d ago

One thing that gets overlooked is how Mercator preserves local angles perfectly, which is exactly what you need when navigating street corners and highway exits. I remember reading that the USGS actually tested a few alternatives for their topo maps back in the 90s and found that Mercator gave the least confusing results for drivers because it kept compass bearings straight. If you use something like the Equal Earth projection for a drive through a city, you might notice intersections looking slightly squashed or stretched, which could mess with your sense of direction at a glance. For turn by turn stuff, a few degrees of angle error can mean missing a turn if you're relying on visual alignment. So while it's terrible for showing the whole world, for the small area you actually see on a phone screen, Mercator is probably the most practical choice.

anderson.spencer5d ago

You know, I was actually reading about this exact thing a while back. There was this study from a university in the UK where they put people in a driving simulator with different map projections and tracked how often they missed turns. Turns out Mercator was way better for quick decisions at intersections because the angles are correct. The other projections made drivers hesitate longer before turning, which is dangerous in real traffic. Have you seen any of that research or is it just something the map nerds talk about?

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