Introducing a new book released by Bureau Gorbunov Publishing—a practigal guide to transit map design. The book speaks of transit map history, important principles of their design, and how they evolve together with their networks. The author talks about techniques: plotting the lines, denoting the stops, choosing the fonts, and composing the final poster.
The book speaks of transit map history, important principles of their design, and how they evolve together with their networks. The author talks about techniques: plotting the lines, denoting the stops, choosing the fonts, and composing the final poster. Not many designers have an occasion to design a subway map. But the principles and techniques discussed are applicable to any tasks of complex information display: org charts, family trees, control‑flow diagrams, fire escape plans, project timelines, military battle schemes, architectural drawings.
After Henry Beck has stopped working on the London Tube map, Harold Hutchinson carried the work on. Hutchinson has abandoned smooth line bends, preferring to just “crunch” the lines at the turns.
This is a very bad map. The fractures is not the only problem with it, but is one of the most prominent.
About Henry Beck:
Turns must be visible, not obscured by the designations of transfer stations.
This is counter‑intuitive: transfers seem to be convenient “pivots”, and it’s natural to want to link them with straight line segments. But it’s important to make the whole route be perceived as one line, not just individual segments between stations.
If you fracture a line under a station, a bad gestalt occurs: the color hints at one relation between the segments; the continuity, at another. It’s easy to get “off track”.
For the color‑blind, such map gets completely illegible: it’s impossible to guess which segment continues which line.
When the turns are visible and lines always pass straight through stations, the eye follows them easily.
This way, the lines stay legible even without color.
About the angle grid:
When designing a geometrical map, a question arises: may there be a double or triple turn? For example, when a 45° grid is used, can you bend a line at a 90° or a 135° angle?
A 90° turn is common. But if there is only one such turn on a map, it may attract too much attention and look as an incoherence of the design. If there are several of them, they look fine.
A 135° turn is questionable. One may argue that the designer has plotted the lines badly if they need turn one of them in the opposite direction.
Sometimes, for graphical unity, designers construct the turn by putting two or three single ones adjacently. But this may make things look worse as well by rendering turns unreasonably clumsy.
Sometimes, it’s possible to hide the problem by moving some station to the middle segment of the turn, as shown on the next spread.
On my Moscow Metro map, the 90° angles are allowed, but I prefer
‘Orehovo’ station is put in the middle a turn segment to justify its existence.
On the 2004 London Tube map, the fragment of theafter Liverpool Street turns at 90°, but makes the next 135° turn to Aldgate East in three 45° steps.
On the 2018 map, the same fragment looks cleaner, with just one 45° and one 90° turn. This became possible after significant changes in the configuration of the surrounding lines .
When a turn is split into segments, those segments must be apparent, i. e. be of sufficient length relative to the bend’s length. In the two leftmost examples, the bends are quite sharp, so the double turn looks conclusive.
If you make the bends smoother while leaving the segments’ lengths the same, a double turn will look mangled. You no longer see an obvious middle fragment, instead, you see a line drawn by a shaky hand.
You may make the middle segment longer, but then the turn will take even more space.
The official Moscow Metro map had such bad turn on theline next to Trubnaya station. Instead of a turn in two steps, there was a mangled line.
In the later version, the flaw was fixed. Also, note a nice juxtaposition of two 90° turns.
Now let’s talk about how to draw the actual bends.
Imagine you are drawing a line with your hand using a brush of a certain width. In this case, to make an abrupt turn you will need to interrupt your motion. In the same way, the eye stumbles upon such turn.
It’s better to at least make the line maintain its width along the turn. Still, the turn is too abrupt.
A simple way to make a turn smooth on a computer is radial rounding. Instead of a corner, an arc of a circle is drawn. The dot • represents the circle’s center.
The larger the radius of a circle whose arc is used, the smoother the line and the easier it is for the eye to follow.
But an overly large rounding takes up too much space on a map, making it hulky. For a great ship, it is difficult to manoeuvre.
When radial rounding is used, for graphical unity it’s better to choose a standard radius for the whole map.
Line bundles will require an exception: if you use the same radius for all lines, holes will occur between them.
To remove the holes, you’ll need to “harmonize” the roundings by fitting:
to the outer one, by reducing the inner ones;
to the middle one, by reducing the inner ones and enlarging the outer ones;
to the inner one, by enlarging the outer ones;
The more lines there are in a bundle, the more options you have.
If you harmonize the bends of the neighboring bundles in different ways, this will stand out.
Harmonize the bends consistently.
The Transport for London standards call for using 45° and 90° turns with radial rounding with a radius of a triple line width.
In bundles, the curves should be fitted to the inner one, by making the outer ones larger.
There is another reason to make an exception to the “one map—one radius” rule.
When the radius is fixed, the length of an arc is proportional to the angle of a turn. A 45° turn is short, a 90° turn is longer, a 135° turn is too long.
It’s better to select an appropriate corner radius for each angle. On the right, the radius for the 45° turn is 1,5 times as big as for the 90° turn. For the 135° turn, it’s 1,5 times smaller. That’s nicer.
Illustrator’s ‘Round corners’ effect has a problem. Only for the 90° turns it uses the radii that you specify. On the right, all lines have the same round corners setting. However, only the yellow one is actually built from an arc of that radius. As you see, the 45° turn has a much larger radius; the 135° turn, a much smaller one.
True radial rounding is achieved with the ‘Live corners’ tool, which appeared in the version 17.1
With radial rounding, a line is constructed by affixing three fragments to each other: a section of a straight line, an arc, and a section of straight line again. This is unnatural: real objects don’t bend like this.
When you bend a steel cane or a shower hose, the curvature smoothly rises in the direction of the center of the bending. It is impossible to say where exactly the “turn” ends.
In the beginning of the chapter I said that fractured lines look bad. Lines with radially‑rounded corners are also fractured in a way: once you see the joints between the arc and the straight section, you won’t be able to “unsee” them.
To smoothen the line in a natual way, you need to pull its Bezier “whiskers” inside the turn, and pull the tie points in an opposite direction. It’s important to not overdo this: if a line starts to look like a macaroni tube boiled too soft, make one step back.
When drawing a 90° turn with radial rounding, the whiskers stick out about 56% of the radius.
A nice‑looking natural curve is usually achieved by pulling the whiskers to about 75%.
When we were looking at radial rounding, we discussed that it was better to select different radii for the turns of different angles.
The natural, hand‑tuned bends will also need to be separately adjusted for each type of turn.
Depending on the angle grid used, you will need to draw by hand a number of different turn segments. The larger the angle, the more pronounced is the difference between radial rounding and natural curves.
When using natural smoothing, the problem of bundles manifests itself in a bigger way.
As usual, if you nest the bends, holes appear. But unlike with radial rounding, here, the holes can’t be eliminated by just adjusting the radius.
Here is an ineffectual attempt to fit all lines to the yellow one. In some places, gaps are still there; in others, the lines overlap.
If the tie points are positioned perpendicularly, you can make the overlap much less noticeable.
Next, you can cheat by putting the lines under each other—nobody will notice the trick.
But if you have spacing between the lines, you won’t be able to hide the imperfection.
You can tell that lines don’t ideally fit each other by looking at the shape of the white spacing. You will need to adjust the bends even more carefully.
But let’s get back to the variant without spacing. We have another problem with it: the green line has fractured.
Let’s try to fix it and fit other lines to it. It’s almost good now, but look at the blue line: its whiskers are not pulled into the angle enough, and so its bend looks too close to radial. If you had more than four lines, the outer ones would be even worse in this way.
To perfect the bend, you’ll need to pull the points of the outer lines farther from the turn to farther pull their whiskers into the angle. Now the bend looks good, and this variant will work with a larger number of lines.
We’ve discussed the situation where a whole bundle is making a turn.
But what if one of the lines goes straight? In this case, the roundings disharmonize unneatly. If we leave the blue line as if it just was the fourth in a bundle, the turn will look too large.
We may draw the bend as if it was the third in the bundle, and it will look neater.
Another option is to smoothen it the same way as the red one. Not too logical, but looks even better.
Or, we may stop thinking of it as of a part of the bundle and smoothen it independently, as a single line.
But the ideal solution is to work‑around the problem by sorting the lines.
On the Australian trains map, the line is not drawn well: on the left, the spacing between it and the blue line is of uneven width. It’s not obvious how to sort the lines to avoid the problem. But if you just make the green line’s rounding smaller and no longer consider it a part of the bundle, it will look better.
Even more noticeable is the problem on the bus map for Riga. The turns look half‑baked: the designer tried to harmonize them, but didn’t succeed.
The perception of the whole map differs depending on the sharpness of its bends, so it makes sense to adjust the smoothing when looking from a distance.
A map with smaller, sharper turns usually looks more rigid, assuring, and mechanical.
Increasing the turns size makes the map friendlier.
On the other hand, the geometry‑ness gets lost.
When a map is close to its final form, іt’s time to fine‑tune the size and shape of the bends. But when all of them are hand‑drawn, changing each just to see if it’s better to the eye, is too much work. Also, there is no way to make sure that all the bends are drawn without a mistake.
That’s why it’s important to be able to adjust all the bends simulataneously.
Tip: make a symbol out of a turn. Adjust the symbol to see how the change impacts the whole map. Here, I’ve drawn a twirl inside the bends’s symbol, and the whole map instantly got twirls.
When there is no angle grid and a map is drawn by a free hand, the standard for the bends quality become even higher. The beauty that arises from consistency and uniformity is achievable by mere carefulness.
But there is a different kind of beauty: the one that arises from immaculate feel and ability to maintain tension in lines. There is not recipe for this. Graphic designers, and even more so, type designers, refine this feel in decades.