GPS and the Marauder's Map

There is a large jump in book thickness when going from Book 3 to Book 4 in the Harry Potter series. Therefore I’ve been slowly working my way through Harry Potter and the Goblet of Fire, reading a couple of chapters each night, instead of trying to read the entire book in one sitting.

A Mary GrandPre illustration of the Marauder’s Map

Where magical objects are concerned, the Marauder’s Map, first introduced in Book 3, also plays an important role in Book 4. The map covers Hogwarts School of Witchcraft and Wizardry, in particular showing dormitories, classrooms, passageways, offices, and more. In addition, the map also shows the location of everyone in the school in real time with their names attached to the map. The third movie does a masterful job representing footprints along with associated nametags when the map is being used.

When I first read about the Marauder’s Map (late ‘90s), I remember thinking what a useful object it was (and I “solemnly swear” that I would use it only when I was “up to no good”). If only it existed in reality. Fifteen or so years later GPS is ubiquitous in smartphones. Not to mention the obvious: smartphones are ubiquitous too. (Back then PDAs were just starting to get popular, but they had not quite combined with mobile phones.) So if everyone carried their GPS-enabled smartphone with geo-tagging on, we could all have our own Marauder’s Map. Not surprisingly, there’s an App for that! Several in fact; you can go download one or more on to your smartphone right now. With wearable technology and personal tracking making headlines – the FitBit Surge has built-in GPS amongst a battery of other trackers – we are perhaps not too far from the dystopian future of having such technology involuntarily embedded into every person. And I'm sure it will be solemnly used for no good.

How does GPS work? Your receiver contacts orbiting satellites and uses trilateration (sort of like triangulation but different) to determine your position. The communication between your GPS and the satellite makes use of radio waves, i.e., long wavelength electromagnetic (EM) radiation. Time synchronization and relative error correction is factored into a calculation, and ta-da, you can now locate yourself almost instantaneously! All this is thanks to electronic devices in your GPS-smartphone and on the satellites. And what are electronic devices? They are simply technological gadgets designed to harness and use electricity.

In Book 3, as part of her Muggle Studies class, Hermione works on an essay titled “Explain Why Muggles Need Electricity”. I’ve been thinking about the relationship between Magic and EM radiation, and that magic is a means of manipulating EM radiation that wizards and witches are capable of, but that Muggles and Squibs are unable to do so. Instead Muggles have built technology around electricity, electronics and electromagnetic radiation. (I wonder if this was how Hermione structured her essay.) EM radiation when appropriately channeled does wonders, in GPS, LEDs, DVDs, and a whole host of other acronyms. Too much or uncontrolled EM radiation renders the devices inoperable, hence the standard EM pulse to disrupt electronics in sci-fi storylines.

In Book 4, when discussing the subject of how Rita Skeeter may be listening in on conversations, Harry suggests that bugs (microphones and recording equipment) might be used. Hermione interrupts: “All those substitutes for magic Muggles use – electricity, computers, and radar, and all those things – they all go haywire around Hogwarts, there’s too much magic in the air.” Is this why the Wizarding world and the Muggle world have "split" into two different tracks? One uses magic, the other uses electronics, electricity and electromagnetism. It was only just shy of 200 years ago that Faraday invented the electric motor. Someone who had not encountered electrical devices would wonder at how they worked. It would be like magic! The “operator” of such devices would be a magician or a wizard or a witch! Perhaps magic and science are not so different after all.