We all know at least one person who is just terrible at giving directions. "Head north on 78 or is it 46? Hang a right at the McDonalds, and when you see a big tree that looks like the dog in that movie, you know the one with Jennifer Aniston where she breaks up with that guy who's in the new movie about Google, make a left there." Wait. What? Where?

Kate McLean, artist, designer, and informational experience design Ph.D candidate, is leading a project, coined Smelly Maps, that could technically do away with verbal directions completely. Her project pays tribute to the neglected power of the nose. Yes, as in your olfactory system, the big ol' honker that allows you to smell the difference between hot, fresh chocolate chip cookies and hot, fresh dog poop. (Too much?)

You might think this is a crazy idea, but believe it or not, your nose is a complex data detective that can discriminate between more than one trillion different odors.

"Hang a left when you come to the fresh scent of pine, a right when you smell hot garbage."

Image: Researchers have mapped what cities smell like. (Guian Bolisay / Flickr CC BY-SA 2.0)

McLean, with the help of the entire Smelly Maps team of researchers, including Daniele Quercia, Luca Maria Aiello, and Rossano Schifanella, marry cartography, urban planning, and social media to present cities. The research began with walking tours around seven cities across Europe and the United States. Participants were exposed to a range of different smellscapes and asked to record their smelly experiences.

For two of the cities, London and Barcelona, those notes were then cross-indexed with geo-specific social media tags from Twitter and Flickr. To structure this large and apparently unrelated dataset of smell words, they built a co-occurrence network where nodes are smell words and undirected edges are weighted with the number of times the two words co-occur in the same items. These smells were then used to create an “Urban Smell Dictionary” consisting of nearly three hundred scent terms.

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In addition to the manual smelling, the team was able to record odors with a device called an olfactometer and head-space 'smell cameras.' "Olfactometers have been used to collect information about distinct odor molecules. They look like ‘nose trumpets’ and capture four main aspects: odor character, odor intensity, duration, and frequency. Other smell recording technologies include a head-space ‘smell camera.’ This device traps volatile odor molecules in a vacuum and is able to capture permanent (i.e., non fleeting) smells."

​The researchers found that the high-level olfactory footprint of Barcelona and London consists of nature and, you guessed it, traffic emissions. Interestingly enough, at street level, streets with emissions words (such as Kensington Road and Park Lane in London) suffer from air pollution, while streets with nature words (such as Hyde Park) do not. Using the collected data, McLean’s team then created the project’s Smelly Maps—graphic representations of what smells can be found where in the cities researched.

Smelly Map of London

How can this research actually be beneficial to us in the future you may ask? The team suggests that new way-finding tools could suggest, not only shortest routes between points, but also routes that are "olfactorily pleasant." Runners, for instance, might want to avoid emission-infused streets when mapping their run route.

While we may not completely turn our noses up (heh) at this odd mapping idea, the likelihood of us fully turning our sense of urban navigation over to a smell-based system will probably not be happening any time soon. The project, however, does offer a unique way to think about our cities, and we can explore just how our noses shape our understanding of where we live. As for my next apartment, I'll opt for the bakery view as opposed to the dog park.


Would you use Smelly Maps to navigate your city? Comment below, or email your comments to