A Mongrel of a Map?


Not a dog.

The Visual System as Statistician

Why does most of the world prefer abstract subway maps like the one shown in (b), instead of the geographically more accurate traditional New York City map in (a)? Is the abstract map less cluttered, and thus more comprehensible at a glance? In ©, we show a "mongrel"of the map section in (a).



I’ve only started the paper; but the map at b) is preferable exactly because it leaves out the geography. When you’re in the subway you’re dealing with nodes and paths – starting at this node, what’s the easiest path to that node?

Before and after, though, you want a surface map with the physical station locations marked, to find your beginning and ending nodes and your routes to and from them.


It seems to be about perception of visual information in our peripheral vision field. Getting information at a glance and planning the next glance.

I was looking for the term for subway-type maps. I believe they are a topological map (not topographical) which is a type of diagram.

A schematic is also a diagram and according to Wikipedia a subway-type map is a schematic diagram. I think the term topological map is better because this type of map usually preserves some scale / distance / direction where a schematic likely does not.


I’m finding it tough going. Looks like I’m going to have to read all the references as well as the FAQ.

So far I’m not clear what their point is, except that they can synthesize images that are different but not perceived as different in peripheral vision.


I searched for “local summary statistics”

A Summary Statistic Representation in Peripheral Vision Explains Visual Search

A major role of peripheral vision, by comparison, is to monitor a much wider area, looking for regions that appear interesting or informative, in order to plan eye movements.

That’s what the first article says, that your peripheral vision helps plan your next glance. A mongrel of a map seems to be a way of illustrating that this “next glance” planning is made more difficult with the more complex map.


I’ve always had a fascination with maps, globes and charts my whole life. I can sit and look at them all day ever since I was a child. Growing up rurally with no experience what so ever with public transportation and being dumped off at a London train station to make my way across town on my own, I was dumbfounded when I saw that map. I mean blown away. I was so unsure of what it was trying to tell me that I ended up taking a black cab and sending the bill to the administrator who almost shit. Or maybe almost shat. After riding a train for a few days into town and following the one they had in the overhead that only had that line on it, it started to make since. I appreciate their simplicity at showing a complicated system and realize that you don’t have to be good at directions or reading maps to understand them. But I still prefer the real thing.


Personally, I always wish the DC metro had maps like (a) so I can see what stop is closest for where I’m going, maybe they should have both.


Veering off the map angle but sticking with graphical display…
I can highly recommend this guy’s books.


I took the course he has and now accepting such poor design is even more irritating to me.
It started for me with how poor some technical manuals, reports are and then during an extended shipyard conversion I wanted to set fire to the walls plastered with excel sheets and work packages not worth anything.

Anyway the books are thought provoking if you have a hand in producing such information. Great section on train schedule layout as well.


That’d been a bad fire at my last shipyard.


Tufte is amazing.


When you go to that link above, click the ET Notebooks tab and pick anyone that looks interesting. The NASA stuff about engineering by power point is quite amazing.


True, but I think it shows something simpler than that, too. A complex, spacially accurate map isn’t a tool for communicating; it is a tool for investigating: a model. A schematic map is a tool for communicating, but not investigating. And this distinction goes beyond maps and applies to nearly all ways of communicating.

A pictogram is a good way to communicate: this way to the exit. A painting is a good way to investigate someone else’s perspective on something. Chief’s standing orders are a good way to communicate what his expectations are. A poem is an invitation to investigate part of someone’s internal world. The fuel oil system is best to investigate with own hands and eyes, but photographs aren’t much good if you want to tell someone else how it works: better to draw a schematic diagram if you want to communicate about it.


Topological maps are there for a purpose. They have to communicate information to masses of people who may have language and spatial awareness difficulties.

The London Underground map by Henry Beck with its octolinear topology was one of the forerunner. It is about the relationship of one station or point to another, not the geography or distance. Beck’s rules in a topological map are indestructible.

A modern proponent is Prof Max Roberts with whom I have been involved in research.



Yes, well put. In general the person who produces a map does not have to anticapate exactly what information the user is looking for. I wouldn’t have thought of night orders vs a poem.

What about the relationship between a schematic and a map? For example in a simple DC electrical schematic the position of the battery in the drawing has no bearing of the logic of the system. But what about a drawing that violates the logic of the system? For example a hydraulic or similar system where a tank that depends on gravity is located in the drawing in the “wrong” place.


The best schematics are created by people who understand what the real situation looks like. If you have a choice about where to draw the battery, you should put it some place that resembles its real location. Header tanks should be at the top, I think most people feel that way. It would be bad communication to draw it at the bottom, or the centre. Form fits function and that is beauty.


Mistaking the map for the territory, evidently a subconscious error. That’s why the rule is trace it out. Sometimes the overconfident or lazy don’t bother.


When you have got to find a valve, its better to all ready know where it is, and if you are going to need a ladder or a valve fork or what-ever. No use wandering around with the drawings and a lamp when something is supposed to be happening already. You can’t imagine my dismay when I was tracing lines and found that the c/o valve between DO and HFO was in the ceiling of the PX room, and didn’t have an extension. There’s only one ladder that can be used to reach it. Why would you put it there? I don’t know the answer, but to most of us it feels like someone “makes the territory from the map.” Mechanics hate engineers (I mean designers, not… you know…) for that reason. Everyone has scars from trying to work on things that the designer didn’t think about: how does a human hand fit into this plan?


Working on deck is the same way. I recall being on the back deck of a tug with a line in my hand that had to be made fast somewhere. Right in front of me at hand level is a cleat.

Next tug, same situation, no cleat to be found.



The Singapore MRT map (by whatever name/type) is fairly simple and straight forward to understand:

It kind of show the lines and stations relative to their map locations, but without cluttering it up with an actual map.

The colour coding has even replace the names of the various lines to where people refer to “I’m living near the purple line” or “Which MRT go there?” “The green line”.


Lines named by color was well established before the Singapore system was built. It was used in the Boston, Massachusetts subway system beginning in 1965. The Washington (DC) Metro system has used color lines since its opening in 1976.

Not surprising the Singapore system would follow suit, as it was designed by a US naval officer (Dennis Ballou) who was a friend of my family. He was in Singapore working on it when I visited there in '85, though I didn’t know it at the time.