ATLAS · FIELD GUIDE
How Trade Flows Are Mapped — and Why Exports and Imports Never Quite Add Up
A container leaves a factory in Vietnam, crosses the Pacific and is unloaded in Los Angeles. Somewhere, two governments write that shipment down — once as an export, once as an import — and once a year the United Nations gathers up every one of those records from every country on Earth. So how does the trade between two countries actually get measured, why do the world's exports and imports never match even though every export is somebody's import, and what are the arcs on this map really showing you?
Trade is one of the oldest things humans do, and one of the hardest to picture. A number like "world trade is worth twenty-something trillion dollars a year" is almost meaningless on its own. What the number hides is the shape of it: the fact that a handful of relationships — China and the United States, Germany and its neighbours, the tight web of trade inside Asia and inside Europe — carry an enormous share of the total, while most pairs of countries barely trade at all. This map is an attempt to show that shape directly, by drawing the trade itself.
What you are looking at
Pick a country and a direction. In exports mode, the map draws an arc from that country to each of its biggest customers — the places it sells the most goods to. In imports mode, the arcs run the other way, from each of its biggest suppliers. Every arc is sized by value, so a thick arc is a large trade and a thin one is small. Choose "biggest flows on Earth" instead of a single country, and the map draws the largest individual trade relationships anywhere — the heaviest threads in the whole fabric.
The arcs curve because the world is a sphere: each one follows the shortest path over the globe between two countries, the same great-circle route a ship or plane would broadly take. That is a visual choice, not a claim about the actual shipping lane — goods rarely travel in a straight line, and much of this trade moves by sea along fixed routes through a few crucial chokepoints. But the arc tells you the thing that matters here: who is connected to whom, and how strongly.
The two-sided nature of trade
The single most confusing thing about trade statistics is that the totals never match, and it is worth understanding why, because it is not an error. Every shipment is recorded twice — once by the country that sends it, once by the country that receives it. If both sides measured the same shipment the same way, the world's exports and imports would be identical. They are not, and the main reason is that the two sides are measured at different points in the journey. The seller records the value at its own border, before shipping. The buyer records the value on arrival, after shipping and insurance have been added. That freight and insurance is real, and it lands only on the import side, which is why the world's imports always total more than its exports.
This map does not try to hide or "correct" that gap. Exports are labelled FOB and imports CIF wherever they appear, so you always know which measure you are looking at. It is the honest way to show trade, and it is why a country's export arcs and its import arcs are not directly comparable.
What the map is not
It is not a scoreboard. A country with thick outgoing arcs is not "winning" and one with thick incoming arcs is not "losing" — importing a lot of goods is what large, wealthy economies do, and a trade deficit is not a debt. The companion maps in the Atlas colour the countries themselves by their total exports, total imports, and the balance between the two, if that is what you want to compare. This map is about connections: the lines between places, and how much runs along each one.
And it is not the whole of world trade. It is close — the countries shown account for the large majority of merchandise trade — but the smallest economies and the newest figures are missing, and a sliver of trade that cannot be pinned to a country is left off the arcs entirely. Every figure traces back to UN Comtrade, the United Nations' record of world trade, for a single recent year. It is a portrait of how the world is stitched together by the things it buys and sells — drawn, for once, as the threads they actually are.
Frequently asked questions
What is a 'trade flow'?
A trade flow is simply the goods moving from one country to another over a period of time, measured in money. When Germany sells 40 billion dollars of cars, machinery and chemicals to the United States in a year, that is one flow: Germany to the United States. The reverse — everything the United States sells to Germany — is a separate flow going the other way. Because trade almost always runs both directions between any two countries, most pairs have two flows of different sizes. On the map, each flow is one arc, drawn from the seller to the buyer and made as thick as the trade is large. 'Bilateral' just means the trade between two specific countries, as opposed to a country's total trade with the whole world.
Who actually counts all this, and how?
Every country's customs service records goods crossing its borders — what the goods are, how much they are worth, and which country they came from or are going to. Countries report those figures to the United Nations, whose statistics division compiles them into UN Comtrade, the world's standard database of international merchandise trade, going back decades. This map uses the annual figures for all goods combined. One useful consequence of everyone reporting is that most trade gets recorded twice — once by the exporter and once by the importer — which lets statisticians cross-check the numbers, though the two sides rarely match exactly, for the reasons below.
Why don't the world's exports and imports add up to the same number?
Logically they should: every export is someone else's import, so if you added up all the exports on Earth and all the imports, they ought to be identical. In practice world imports always come out larger, and the main reason is how the two are valued. Exports are usually measured 'FOB' — free on board — meaning the value of the goods as they leave the exporting country, at the ship's rail. Imports are usually measured 'CIF' — cost, insurance and freight — meaning the value when they arrive, which includes the cost of shipping them across the ocean and insuring them on the way. That shipping and insurance is real money, and it gets added to the import side but not the export side, so the world's imports total up to more than its exports. There are smaller reasons too — goods in transit at year's end, different reporting dates, simple errors — but the FOB-versus-CIF gap is the big one. This map keeps the two figures honest by labelling every export FOB and every import CIF rather than pretending they are the same measure.
Why does the same shipment appear twice?
Because trade is a relationship, not a one-way street, and the map shows direction. The goods China sells to the United States and the goods the United States sells to China are two different things of very different sizes, and each is drawn as its own arc. So when you look at the 'biggest relationships' list you may see a country pair listed twice — once for what each side sells the other. That is not double-counting a mistake; it is showing you that trade flows both ways, and letting you see the imbalance between the two directions, which is often the interesting part.
Does the map show every country and every good?
Almost, but not quite. A country appears once it has reported its trade for the year, and the newest and smallest economies often file late or not at all, so the map covers close to nine-tenths of world merchandise trade rather than the whole of it. It also combines all goods into a single figure per partner — it does not yet break trade down by product, so you cannot see here whether a flow is oil, cars or coffee. And a small slice of every country's trade is logged not against a specific country but against groupings like 'areas not elsewhere specified', ships' stores, or tiny territories with no outline on a world map; that trade genuinely cannot be drawn as an arc between two points, so it is left off rather than invented, and each country page tells you how much of its trade is shown. Finally, these are annual figures refreshed once a year, not a live feed — trade does not change second by second the way a flight or a storm does.
SEE IT ON THE MAP
Everything in this guide is on the live Atlas map.