How city “smell-mappers” can help with virtual reality, real estate and how we understand the past

Tulips on the Dam Square for National Tulip Day: one of the nicer smells you'll encounter in Amsterdam. Image: Getty.

Data scientists, artists and urban planners are mapping digital “smellscapes”, opening up new possibilities for virtual reality, real estate and how we understand the past. In the process, they are provoking interest from the UK’s biggest conservation charity. All three groups are exploring the ways in which smell influences environmental perceptions, using social media data and “smellwalks” to trace olfactory tendrils stretching through city streets.

Luca Maria Aiello is part of a group of researchers with GoodCityLife.org, which maps urban smellscapes by tracking keywords online. It creates skeletal road maps with colour-coded strips: red for emissions, green for nature, blue for food, yellow for animals, and grey for waste. The Bayshore Freeway in San Francisco, for example, predominantly smells of emissions, according to the data. The project also ranks “Likeability”. The emotion most commonly affiliated with the freeway is “sadness”.

Aiello and colleagues compiled the percentages with the aid of the work of the late British urban planner Victoria Henshaw, and began their research by collating a dictionary of smell-related words she listed. “It was our first feat to look for words in social media, and then we [produced] ... some sort of class word to put all these words together in microcategories,” Aiello explains.

Henshaw undertook smellwalks as part of her doctoral research, publishing a book called Urban Smellscapes in 2013. She used qualitative methods “including semi-structured interviews, participant drawings and direct observations” rather than social media data. GoodCityLife uses geotagging, and sifts through Twitter and Instagram to collect terms. 

At this point, says Aiello, they could “map all the major cities in the world”. So far, they have traced the smells of 12 different cities “without spending too much money because this data can come for free from the public in the area”.

He acknowledged the potential for ‘noise’ in the data; corroborative evidence is vital in being able to compile accurate maps. Data availability levels are shown alongside street maps, and in some areas it is still low: further documentation is vital.

British artist and designer Kate McLean steps away from the “big data approach”, preferring the more “human” practice of walking out into the city. Aiello and his team used McLean’s methodology “as a way of confirming the data they gathered through hashtags,” McLean says. 

 

A detail of Kate McLean's smallmap of Amsterdam.

On 28 February and 1 March, McLean will conduct two smell walks in London in conjunction with the Museum of Walking and The Flower Hut. She delightedly recollected previous events. “We had a group of 10 or so people going up to this biker and asking to smell him – it’s not illegal to smell people – just impolite,” she says.

She recalled a nonsmoker on a London smellwalk, who asked a stranger to breath a cloud of tobacco smoke on him. He just “really wanted to understand it,”she says.  Recalling a trio to Pamplona, she says: “You get people arguing about what is being cooked five storeys up.” The olfactory cues acted as precursors to “imagined worlds”, where some visualised “a meat stew with tomatoes” being cooked and others bolognese.

Combining such work with the internet opens up several new possibilities. Aiello points to the implications for virtual reality. “You can think about an application that lets you explore places remotely... not only the visuals but the full sphere of perceptions of a space.”

He also details how it could affect the real estate market. House values should hopefully “reflect the positivity of the environment,” he says, adding that he hopes “to work with city officials to put up targets for interventions” as senses correlate with “something very tangible, which is the health of the citizens.”

 

Another detail of Kate McLean's smallmap of Amsterdam.

The UK’s National Trust is also mulling the incorporation of smells into its visitor interaction, says McLean, to get people to “think about smells, but contextualised,” she said.

Nicky Boden, a visitor experience consultant with the Trust, confirms that it is looking into the possibility, but adds that this is specifically in the Midlands rather than on a national scale. “We are interested in trialing some new approaches to ‘tours’ or managed experiences which are more participatory and draw on the senses to create a deeper connection with people and place,” she says.

Conveying smell is a different issue. Last October, San Francisco-based artist Laurie Halsey Brown, conducted a smell walk around the Presidio, a park in the northwest of the city. Afterwards she produced psychogeographic art ‘kerchiefs, with “light variances of the image reflecting how smells dissipate and linger, with some locations having stronger and weaker areas of scent”.


McLean’s smell maps are usually animated; she believes motion better indicates the temporary quality of smell. “If I’m mapping something that disappears into nowhere, surely that map should not actually stay fixed,” she says.

Aiello took a less flexible approach. “It’s a bit evanescent but it’s also quite easy to map smells into an object from which a smell originates,” he says. “It’s a little bit trickier if you want to map even more subjective concepts like happiness and so on.”

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The Delhi Metro: How do you build a transport system for 26m people?

Indraprastha station in 2006. Image: Getty.

“Thou hath not played rugby until thou hath tried to get onto a Delhi Metro in rush hour,” a wise Yogi once said.

If you’ve never been on New Delhi’s Metro, your mind might conjure up the the conventional image of Indian trains: tawdry carriages, buckets of sweat, people hanging out of windows and the odd holy cow wandering around for good measure.

Well, no. The Delhi Metro is actually one of the most marvellously sophisticated, affordable, timely, and practical public transportation systems out there. On a 45C day in the Indian summer, many a traveller has shed tears of joy on entering the spacious, air-conditioned carriages.

Above ground, Delhi is a sprawling metropolis of the scariest kind: 26m people, three times the population of London, churn and grind through Delhi itself.

The National Capital Region, an area which includes Delhi and its surrounding satellite cities – now victim of its never-ending urban sprawl – has an estimated population of almost 50m. So how do you tie such a huge population together?

The map; click to expand. Image: Delhi Metro Rail.

Motorised vehicles won’t do it alone. For one, air pollution is a horrific problem in Delhi, as it is across India. Last November, the government declared a state of emergency when the Indian capital was engulfed by a toxic, choking fog so thick that you could barely see several metres in front of you, drawing allusions to the great Victorian fogs in London.

Then there’s Delhi’s famous traffic. Twenty-five years ago, the travel writer William Dalrymple observed that you could reduce the Delhi’s road laws to one simple idea: the largest vehicle always had the right of way. The traffic has tamed somewhat in the 21st century, but the number of vehicles has multiplied again and again, and it’s not uncommon for people to be stuck in four-hour traffic jams when they try to traverse the mighty city.

Enter the Delhi Metro – a huge network of 164 over- and underground stations – and by any account, a titan of civil engineering and administration.

The numbers are simply colossal. Every day the metro serves on average almost 3m people. Annually, it carries around 1bn.

In a country where intercity trains still turn up a day late, the Delhi Metro is extraordinarily timely. On the major lines, trains will come every several minutes. The trains are extraordinary speedy, and you’ll reach your destination in a fraction of the time it would take for you to drive the distance.

The minimum fare is 10 rupees (12p); the maximum fare, to and from the airport, is 50 (60p).

The evolution of the metro. Image: Terramorphus/Wikimedia Commons.

Construction of the metro system began in 1998, with the first section completed in late 2002. Keen to avoid the catastrophic corruption and bureaucratic mismanagement which plagued eastern city of the Kolkata Metro, developers took advice from Hong Kong’s high-tech system There have been several stages of development to add extra lines; more is planned. By 2020, it is hoped that the 135 miles of line will have increased to over 300.  

One thing quite striking about the metro is its women’s only carriages at the rear and the front of the train, marked by pink signs. Sexual assault and harassment has been a horrific problem on Delhi’s transport systems. Women can of course go anywhere on the train – but men who violate the carriage system will have to deal with the scathing anger of the entire pink carriage.


One of the under-discussed impacts of widespread and well-used public transportation systems is their propensity to break down social and class barriers over time. As the London Tube began to be used more and more in early 20th century London, people from completely different walks of life and classes began to brush shoulders and share the same air.

The story is similar in Delhi. The necessity of the metro helps to break down old caste and class divisions. Of course, many elite Delhiites would not be seen dead on the metro, and choose their private chauffeur over brushing shoulders with the common man. But slowly and surely, the times are a changing.

What’s more, the Delhi Metro system is one of the greenest around. Six years ago, the Metro was the first railway system in the world to be awarded carbon credits from the United Nations for helping to reduce pollution in the capital by an estimated 640,000 tonnes every year.  

All praises sung and said, however, at peak times it’s less mind the gap and more mind your ribs – as a fifth of humanity seems to try to get on and off the train at once.

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