Just before I started working on my novel, Eggshells, I was flicking through a street atlas of Dublin. I used a pocket atlas because I didn’t have a smartphone then, and when I went to meet somebody someplace I hadn’t been in the city, I needed to figure out how to get there the old-fashioned, paper way. At the back of the atlas, an index contained some place names and street names that sounded otherworldly, as if they came from fairy tales, so I made a list of those names: for example, Dolphin’s Barn, Prince’s Street, Curved Street, Thundercut Alley.

My character, Vivian, grew from these imaginings. Vivian made the same list of magical-sounding places in Dublin and spent her days walking to these places in an attempt to find a portal to another world. When she returned home from these walks, she traced her routes on a large old map with thumbtacks, imagining what shape each route could represent.

I walked these routes myself, and plotted them afterwards on a map. The shapes I came up with, the shapes that Vivian decodes (“a Turkmenistan with a tail,” “an upside-down and back-to-front Chad”), grew from some factually incorrect, imaginative leaps: I plotted the walking routes very roughly and made spatially flawed sketches based on the resulting shapes. These fictional map outlines form the basis of Vivian’s pattern-seeking.

Looking so closely at the city map made me see connections between the streets of Dublin, shortcuts I hadn’t noticed in three-dimensional perambulatory reality. I saw that I had been putting an extra mile on the four-mile walk between my house and my parents’ house by adding a needlessly circuitous street. The shape of the street would have eluded me had I not peered at a map.

I hadn’t heard the word “psychogeography” when I was writing the book, but, once I was finished, suddenly it seemed to be everywhere. I like the concept, the idea of walking a place and coming up with personal reflections in some way connected to it, or deciding what you’ve figured out about yourself on those walks. My character Vivian doesn’t do too much soul-searching, however. Her searching is more outward and literal: seeking a doorway or portal, and not questioning her motives too much. She is very certain about her own motives; it’s other people’s that cause her consternation.

My own first dealings with a city are usually on foot; it’s how I make sense of a new place. I take buses and trams and trains too, but if I can, I walk. This is possible in a compact city like Dublin. I don’t drive, which makes me a very irritating navigator in a car; I only know the city at walking pace and am not familiar with one-way streets, prohibited turns, and so on. My sense of a city is in the shortest route between two points or, if it’s very late on one side of the day or very early on the next, the brightest most populated streets.

I find maps difficult to read. I love them and obsessively buy them and collect them and display them (old ones are best, with fewer colours and large landmasses now streaked with black lines). I like looking at them and sounding out the place names and imagining future travel adventures, but I struggle to read street maps with their function in mind; that is, with a view to telling me which way to go next. I can find my current position—those red YOU ARE HERE arrows on public information signs are very reassuring—and I can figure out my desired endpoint, but the bit in the middle is a right terror. Maps—the ones you want to use in a practical way—are a tyranny of lines. Flicking between the legend and the map to figure out which is a road (and, which is a road that allows foot traffic) and which is a river and which is a railway track takes all the good out of it for me, and I get distracted by interesting-sounding place names that will take me far from my endpoint if I decide to follow them.

My first attempt at deciphering a new city was in New York at the end of the last millennium. I spent a summer working as a carer for an agency, figuring out how to get to the apartments of different patients by subway. My sense of New York developed from these ventures. I knew pockets of the different boroughs, but I had no sense of how they connect. Even though I studied maps of Manhattan, with its simple grid formation and easy-to-follow street and avenue numbers, I couldn’t reconcile this map with my own personal view of the disconnected areas. My sense of London is the same: I have an unrealistically linear, colour-coded version of the city in my head. I have probably taken a number of complex Underground trips, going to the effort of changing trains to travel between two points that may be quite close to each other in reality, and which I could have been quicker walking between.

Dublin’s transport is built on the flat; we have no underground trains, but politicians’ subterranean promises are renewed in the run-up to elections. I love travelling by underground rail; it’s the first thing I check for when I visit a new city. I particularly like the trains with long vertical seats facing each other. In these carriages, I wonder where everyone is going and what’s in their shopping bags and why they’re smiling as they check their phones. When the seats all face the front, I don’t wonder these things.

I struggle to get a read on cities that are built for motorists rather than pedestrians, with footpaths that refuse to take you the direct route between two points, or worse, footpaths that come to sudden, jagged stops. Cities in which the building you want to get to is visibly close but is clogged by a concrete burden of underpasses and overpasses and pedestrian-less routes. Cities in which you take transport from one place of interest to the next, with no wanderings in between.

Cities with no definite centre make me uneasy. I spent a year in a northern Japanese city whose centre had lapsed into decline. Two large shopping malls on the outskirts of town had become the new hubs. This was a bother to my wanderings: the museum was outside the city, there weren’t many shops open in the city centre, and those that were still open felt deserted. The empty streets were made all the eerier by the tinny, superfluously cheery children’s songs being played over an outdoor PA system; there was something of a horror movie about it. This city was navigable on foot, with few sights to hunt out, so I was able to wander map-less, but, try as I might, I could neither get lost nor happen across something unexpected. I spent my time in a donut chain by the train station; if I couldn’t find city-specific cafes, I was sure as hell going to enjoy the muted, generic urban experience.

Eggshells is on sale now. Buy your copy here or at your neighborhood independent bookstore.