Navigation or Legibility – Which Way?

Fanis Grammenos returns to the subject of urban form, this time to interrogate the connection between legibility and navigation. In this essay, he considers whether an orthogonal city layout aligned with the cardinal directions is a necessary condition for easy city navigation. 

In an earlier article, Beloved and Abandoned, we presented the grid plan, using Portland's layout, as a historic relic perhaps deserving of attention but clearly unfit for replication in contemporary settings.  That, evidently, is not occurring in any case. Several commentators quickly pointed to the supreme legibility of the simple grid as a counterpoint; clearly an indispensable attribute, they said. But is it?

The value of legibility lies in its presumed link to navigation.  It is assumed that good legibility makes navigation easier.  But does it? Is a simple, orthogonal geometry aligned with the cardinal directions a necessary condition for easy city navigation?  Apparently not, as we shall see.

Though related, the two concepts, navigation and legibility, are quite distinct.  One is about an act and the other about a mental construct.  "Navigation" and "way-finding" appear interchangeably in architectural and planning literature and they both mean reaching a destination with ease.  "Legibility" which originates from text reading, is harder to grasp, but it does relate to a map in the mind, be it a letter, a picture or a configuration of streets.  Legibility expresses the ability to project an image and discern its match with what one sees.  Navigation as an act could be compared to dancing – a sequence of rhythm-coded steps that is partly or entirely preset and that becomes intuitive.

The first notion to consider in deciphering this puzzle is that navigation, or finding one's way to a destination, not only predates geometry by millennia, but it is also a basic skill of most sentient, even "non-intelligent," life.  Examples abound from bees to birds to fish and turtles and many more.  Closer to home, emotional, and sometimes incredulous, recounting of pets returning from a distant foster home, point to that instinctive ability.

In humans, a few striking examples, first from the non-urban world, show the distinctiveness of the two concepts and the independence of navigation from geometry.

Inuit will trek for many kilometers beyond the base horizon in pursuit of game, often in poor visibility, in what seems an undifferentiated, unremarkable, featureless landscape and, surprisingly to us urbanites, find their way to a destination and back home with astonishing efficiency.  Legibility, understood as a geometric order or map, is entirely irrelevant in this landscape.

Figure 1. The feat of seafaring for thousands of kilometers in the Pacific Ocean without a single navigation aid still astonishes cultural anthropologists and navy captains, by user: Makthorpe [Public domain], via Wikimedia Commons

An even more astonishing example comes from Polynesia.  For many centuries before they were "discovered" in 1595, the Marquesas inhabitants had ploughed the vast Pacific Ocean in stone-age-tool-crafted open catamarans to trade with and settle in other distant pacific islands.  The crew of ten included a captain and a "wayfinder", two very distinct roles (the wayfinder does not sleep!).  Not a single navigational aid existed on board.  These seafaring traders and settlers were able to regularly reach distant ports well beyond the visible horizon, often thousands of kilometers away, with accuracy and efficiency that surpassed by far the skills of fully equipped European sailors.

A great captain, Magellan, for example, sailing west from Cape Horn, missed the Marquesas and other pacific archipelagos to land, months later, with a malnourished and decimated crew, on Philippines.  The Marquesas wayfinder "knew" his directions with infallible precision. Nothing could be less "legible" and more disorienting than a vast, featureless ocean during weeks of sailing.  Evidently in this case, legibility, as a geometric construct, has little to do with navigation.

Figure 2: A typical medieval city street network within a perimeter wall, now a peripheral arterial. Visitors get easily lost in the maze, but not its residents.

From the urban world, examples also show that navigation does not depend on legibility.  Most visitors describe Arab cities such as Fez, and Marrakech or Medieval cites such as Vienna and Martina Franca (Fig.2) or Asian cities such as old Tokyo and Mumbai, as mazes, impossible to navigate even with a map in hand.  In each case, the street pattern lacks clear geometry, has no uniformity or repetition, is rarely rectilinear and seldom abides with cardinal directions.  Yet for many centuries, the residents of these cities thought nothing of navigating through their streets.  Even more surprising, these same labyrinthine streets had no names and house numbers, yet posed no difficulty to reaching destinations.  Intensifying the surprise, are the cases of planned Roman cities with a highly legible orthogonal grid that were transformed into maze-like patterns by their subsequent occupants as if legibility was undesirable.

Figure 3. Old Vienna's street network is typical of many medieval cities: irregular, idiosyncratic, varied bock sizes and shapes with multiple orientations, maze-like. (green indicates pedestrian-only streets) Giving verbal instructions to a destination could be an insurmountable challenge; following them, an impossibility.

If navigation was not an issue in these early pre-urban, non-urban and urban conditions, then the introduction of a simple geometric arrangement of straight streets and repetitive blocks would seem unnecessary for that purpose.  In fact, Aristotle, long after Hippodamus drew the famous grid plan of Miletus, argued against his configuration and in favour of the old, "organic", labyrinthine pattern on the grounds of defence, as did Alberti 1,500 years later.  Camillo Sitte made the same case on aesthetic grounds, entirely unconcerned about legibility, having lived in Vienna, (figure 3) a medieval city, and grown to admire many other similar cities, with irregular street patterns.

These examples show clearly that humans on foot, on horses, carts and in boats have been able to find their way to a destination in natural, non-urban and in urban environments unaided by geometry and printed maps.  The one presumed outstanding feature of the simple grid, legibility, proves to be unnecessary for navigation and simply an after the fact attribution by post-Guttenberg humans looking at maps.

Fanis Grammenos is a principal of Urban Pattern Associates and was a Senior Researcher at Canada Mortgage and Housing Corporation for over 20 years. He focused on housing affordability, building adaptability, municipal regulations, sustainable development and, recently, on street network patterns. Prior to that he was a housing developer. He holds a degree in Architecture from the U of Waterloo.



One significant difference

Although the examples of cities cited here all predate the automobile--which works well for an a walkability argument--I wonder if the much more limited mobility and geographic scope also played a role in the development of individuals' cognitive maps. Mr. Grammenos describes pre-industrialized and certainly pre-globalized cities, where people would likely live their entire lives within a short distance of where they were born, allowing a level of familiarity with an irregular layout of a city starting at an early age and building on it throughout their lives.

Contrast that with today's cities--which tend to be considerably larger--and people's mobility--again much greater than in the past. Without the benefit of living and learning the particular geography of a single, relatively compact city, legibility does seem more important for wayfinding than in the past.

It's been a few years since I read Lynch's Image of the City, but as I recall, he makes the case that people can quickly learn to navigate smaller, less legible areas more easily as long as these areas are a small part of an otherwise legible larger geography. I'd be interested in others thoughts on this.

For non-Polynesians

I think you're right, but I also find that the essential distinctive of a grid [for navigation] is that when you move from parallel to parallel, you deal with the same point on each line. What is obvious visually is difficult to cast in words, but what I mean is this:

When you travel any other map than a grid, you change latitude *and* longitude, navigating both shifts at once, and this makes it vastly harder to keep track than when you arrive across the coordinate system one coordinate at a time, right?


Missing the Point

For defenders of formal grids, like myself, I can't help but sigh when I read pieces like this. Mr. Grammenos misses the point of our arguments.

First, and most importantly, the formal grid patterns that we defend are by no means common practice in current urban design efforts. For decades, we've been influenced by city beautiful and garden city design ideals, for which there is hardly ever a straight street. This has carried over to New Urbanist design, which garnered many projects the label "New Suburbanism", as they in practice have many similar patterns with modern suburbia. And, in places that do have formal grids, they've been under attack for decades by urban renewal, super-blocks, highways and more.

Despite all this, a quick survey of North & South America would show that the vast majority of places where people actually do find their way around by foot or bike are in these formally-planned grids. This is not theory, or the 15th century - it's today. Our argument - we should study more thoroughly why this is the rule, rather than be obsessed with the exceptions. And, it would make sense to celebrate those aspects that work. For example, yes, it does make sense that as human beings we like to orient ourselves by the sun and the moon, and that cardinal directions mean something.

Lastly, by no means do I think those more medieval-inspired plans should be removed from our toolkit. We do have some places in the Americas with wonderful examples, and I personally enjoy them as much as the grids of say, New York, Chicago, San Francisco or Savannah. So - why is there always a push to eliminate tools from our arsenal? Let's understand what works in reality (and why), before we split so many hairs about what might work theoretically.


Urban design toolbox

I like the comment about having more tools in your toolbox. Grids work--period. Why not utilize them?

Paul Knight

Navigating with the grid

I will leave the question regarding "legibility," or how one reads a city, to others; that question seems like a philosophical rabbit hole. But I will comment on one of the other main points of the article: that navigation is independent of geometry. If everyone in history got lost in their own medieval cities all the time I'm sure the grid would be everywhere, but it's not. Of course people can navigate outside of the grid. Even during my first day in Venice I was able to get around with relative success. So the question is not whether a non-grid is navigable but how much more navigable is a grid over a non-grid.

The grid's power is in the instant mental map that it creates for us along with the ease in its potentially infinite expansion. A few examples:

My first day in Venice I could feel my way around, but during my first day in New York I knew precisely where I was in the world.

After the 1785 Land Ordinance organized the West using the grid, someone could step into an office in Ohio and buy a plot of dirt 800 miles away site unseen. They could then venture off and know precisely where they needed to go. The grid makes the unknown immediately known (and sellable).

Never mind sailing's reliance on the grid. The article seems to suggest that sailors today should dispense with those pesky latitude and longitude coordinates.

All of my clothes are in a grid of drawers for ease of access and navigation. Would I be better served tossing them in piles throughout the room?

Simply put, the grid abstracts locations for us, the non-grid does not. The grid organizes our built world and pre-organizes our unbuilt world.

Paul Knight

Michael Lewyn's picture

I sure wouldn't want to visit there

Grid-less cities like downtown Boston are fine if you've lived there forever- but visiting there was definitely pretty difficult!

Grid Plans

Grids are not generally workable for areas like Chattanooga Tennessee, which is decorated with a number of steep ridges as well as a number of streams and rivers, which wind and twist. Bridges, tunnels and road-cuts are made where practical.

Ralph Boroughs

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