Thursday, July 29, 2010

Reading Maps, or How I learned, yet again, that it is never safe to make assumptions

When I was an undergrad enrolled in a Field Methods course my teacher wouldn’t even talk to us about the map unless we first “oriented” it (aligning the north arrow of the map with the north arrow of our compass). This is a very sensible idea, as one is much less likely to confuse one’s location by thinking that this hill on the map is that hill in the real world, when, really, it is the other hill over there. However, when printed in a book or posted onto a sign maps are often oriented with a “north at the top” convention.

Before today I would have used the word “always”, rather than “often”, but today I found out that the maps in Glasgow, Scotland are not oriented with north to the top. I have just spent a week visiting friends in Edinburgh (and enjoying the fact that the temperature was nice and cool—unlike southern Europe was before I left), and my return flight was out of the RyanAir airport in Prestwick (which is not that far from Glasgow). To get there from Edinburgh one takes a train to Glasgow Queen Street Station, and walks from there to the Glasgow Central Station to board the train to the airport.

I had thought about printing a map from google of Glasgow city centre before traveling, but forgot to do so before shutting down my computer. However, I didn’t worry about not having a map of my own, since I’d seen a Glasgow map and I knew that the two stations were quite close to one another; my destination is about two blocks west and 4 or 5 blocks south of the station to which I would be arriving. In addition to that information, my friend also told me that there are maps of Glasgow posted on signs in quite a few locations in the city center, especially near the train station, so I knew I could look this information up again when I got there.

When I arrived in Glasgow I exited the train station, looked around, and saw a map just up the street. When I reached the map I looked at the street signs for the intersection upon which I was standing to learn their names, then looked at the map (marked with a “you are here” arrow and a large circle of everything that the mapmaker thought was within a five minute walk of that point). Sure enough, the “you are here” spot was located at the intersection of the two streets whose signs I’d just read.

However, the bottom of the map ended only a couple of blocks below the “you are here” mark, just outside of afore mentioned large circle. Central Station was not visible at the bottom of the map (where I expected it to be, since I was using the assumption that the map was oriented with the top = north convention). Therefore I reasoned that the station I wanted is located just off of the area covered by the map, and I started down the street in what I assumed to be the correct direction.

One block later I found another sign with a map posted on it, but much to my surprise, there was still no Central Station at the bottom of the map. However, looking closer at the map I discovered that the station is on the map, but instead of being where I expected to find it, it was located near the top of the map.

A more careful perusal of the map in front of me revealed an over-street foot bridge located just above the “you are here” marker on the map. Looking past the map I saw that there is, in fact, such a foot bridge over the street in front of me. Ah-Ha! This map is not oriented “north = top”, it is oriented “top” = “direction you are facing as you look at the map”.

This prompted me to search the map for any sort of north arrow. There wasn’t one. Therefore, in order to determine that “up on the map” = “direction you are looking” one would need to either expect it to be so, or take time to do a careful comparison of the map with the real world. Fortunately, I’d only walked one block out of my way, so no harm was done, and I now know to take just a bit longer when reading maps posted in strange towns to see which convention (if any) they are using for how the maps are oriented.

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