Perfecting
To perfect a sheet is to turn it over and print the reverse. This one turns the Earth: nineteen stations set beside their antipodes as a two-plate register, with the section through the centre drawn between them, and every plate pulled from the public map embed — no key, no API.
Register of the reverse side
19 stations · 10 land · 9 water
35°40.9′N 139°46.0′E
35°40.9′S 40°14.0′W
The register
Numbered east from the 180th meridian. Choosing a line turns both plates.
Notes on the sheet
- Straight through the centre
- 12,742 km
- Over the surface, on any bearing
- 20,015 km
- The second divided by the first
- π ÷ 2
- Difference in local solar time
- 12 h exactly
- Every great circle drawn through a point comes back to its reverse, so from any station there is no wrong way round: north, east and south-west are all the same distance.
- 10 of the 19 reverses printed here fall on land. The Earth manages roughly one in twenty-five. This register is not a sample — a blank plate is the ordinary result, and the harder thing to make a page out of.
- Nos. 07 and 18 are one pairing read from either end; turn either sheet and the other station is nearly under the pin.
- Positions are given in degrees and decimal minutes. A sight taken by hand is reckoned from the same two lines — 0°0.0′N at the equator, 0°0.0′E at Greenwich — and carries no note of the ground, because the plate is the only answer this sheet has.
Perfecting
In a printing house, to perfect a sheet is to turn it over and print the second side. The paper comes back through the press upside down and back to front, and what lands on it has to register against something it can no longer see.
This sheet perfects the Earth. Every point on the surface has exactly one reverse — its antipode — and the arithmetic that finds it is so short it is almost disappointing: flip the sign of the latitude, and move the longitude half a turn. Tokyo at 35°40.9′N 139°46.0′E is backed by 35°40.9′S 40°14.0′W, and that is the whole calculation. The interesting part is not the sum. It is what turns up when you actually go and look.
The two plates
Recto is the station. Verso is what is directly beneath it, twelve and a half thousand kilometres down and out the other side. Both are pulled at the same scale from Google Maps, so the comparison is fair: the same square of the world, printed twice, once from each end of a line through the centre of the planet.
The plates arrive in the sheet’s two inks and stay there until you look straight at them — bring a plate to the middle of the screen and the colour comes back, the way ink lifts off a proof held up to the window. Choosing a scale changes both plates together, because a chart that shows one side at ten kilometres and the other at a thousand is not a comparison, it is a trick.
The section between them
Between the plates is the section: a slice through the Earth taken along the great circle that carries both points. The equator runs across it as a broken line, the axis stands through the poles, and the two marks sit on the rim at their true latitudes — solid for the station, open for the reverse, the way a chart distinguishes a position fixed from a position merely reckoned.
The black line joining them is the chord, 12,742 km, and it is the only straight road between antipodes. The fluorescent arc beside it is the surface route, 20,015 km, drawn as half the rim — and it is drawn as any half on purpose. Every great circle through a point returns to its reverse, so from any station on this sheet there is no wrong way round. Due north, due east and south-south-west are all exactly the same distance.
The register
Nineteen stations, numbered east from the 180th meridian, so the number itself says where in the turn you are. Each line carries its position, its reverse, and a note of what the reverse turns out to be. Choosing a line turns both plates; inside the register, ↑ ↓ step through it.
Ten of the nineteen reverses fall on land, which is a wildly unrepresentative figure and is meant to be. On the real Earth something like one point in twenty-five has land on both ends — the two big landmasses sit on opposite sides of the same hemisphere of water, and most of what you would find by digging straight down is the Pacific. A register that sampled honestly would be seventeen blank blue plates and two towns, which is the truth and not a page. So this one is stacked, and says so.
What survives the stacking is the good part: Perth comes out seventy kilometres from Bermuda; Rapa Nui, the most remote inhabited island in the Pacific, is backed by the Thar Desert; Suva reaches Timbuktu. And London’s reverse falls about 220 km short of the Antipodes Islands, which is why they carry the name — sighted in 1800 and christened Penantipodes, “next to the antipodes”, by a crew who knew they had come close and were not going to claim more than that.
Nos. 07 and 18 are one pairing read from either end. Turn Madrid and you land in the Tararua hills; turn Wellington and you land in Castilla y León. Neither is exact, and the two errors are the reason both are here.
| Control | What it does |
|---|---|
| A line of the register | Turns both plates to that station and redraws the section |
| Scale | The zoom level of both plates at once, from the hemisphere down to the street |
| Ink | Chart or photograph — the map plate or the satellite plate |
| Take a sight | Any latitude and longitude you like. The register has no note on the ground there, so the plate is the only answer the sheet has |
On borrowed plates
There is no API key anywhere in this piece, and no map library. Each plate is the public Google Maps embed — the same URL the share dialogue hands out — dropped into a frame and run through the site’s two-colour treatment with a CSS filter. Choosing a station builds a new frame rather than reassigning the old one, so turning the sheet twenty times does not leave twenty entries in your back button.
The consequence of borrowing is that the plates can fail to print: a blocked frame, a network that will not reach Google, a browser that refuses third-party embeds. That is survivable here, because none of the sheet’s information is inside the frames. The register is set at build time and the section is drawn from the coordinates, so with the plates dark the page is still a complete list of nineteen positions and their reverses — a chart with the survey printed and the photographs not yet pasted in.
What it is for
Nothing, in the useful sense. But the two-plate form does one thing an ordinary map cannot, which is to make the far side of the planet a physical fact about where you are standing rather than a place on a different sheet. Every point you have ever stood on has had one of these underneath it the whole time, and for most of them the honest answer is open water at a depth of four kilometres, unvisited, unnamed, and exactly as far away in every direction.