science

UN/LOCODE

UN/LOCODE is a science topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand UN/LOCODE rather than just read about it. In short: UN/LOCODE, the United Nations Code for Trade and Transport Locations, or in a more simplified form United Nations location code, is a geographic coding scheme developed and maintained by United Nations Economic Commission for Europe (UNECE). UN/LOCODE assigns codes to locations used in trade and transport with functions such as seaports, rail and road terminals, airports, postal exchange offices, and border crossing…

Key takeaways

UN/LOCODE belongs to science; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect UN/LOCODE to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of UN/LOCODE from memory before moving on to harder problems.

Reference excerpt

UN/LOCODE, the United Nations Code for Trade and Transport Locations, or in a more simplified form United Nations location code, is a geographic coding scheme developed and maintained by United Nations Economic Commission for Europe (UNECE). UN/LOCODE assigns codes to locations used in trade and transport with functions such as seaports, rail and road terminals, airports, postal exchange offices, and border crossing points. The first issue in 1981 contained codes for 8,000 locations. The version from 2011 contained codes for about 82,000 locations.

Structure UN/LOCODEs have five characters. The first two letters code a country by the table defined in ISO 3166-1 alpha-2. The three remaining characters code a location within that country. Letters are preferred, but if necessary digits 2 through 9 may be used, excluding "0" and "1" to avoid confusion with the letters "O" and "I" respectively. For each country there can be a maximum of 17,576 entries using only letters (26×26×26), or 39,304 entries using letters and digits (34×34×34). For the US, the letter combinations have almost all been exhausted. So in 2006, the Secretariat added 646 entries with a digit as the last character.

Loose consistency with existing IATA airport codes For airports, the three letters following the country code are not always identical to the IATA airport code. According to the Secretariat note for Issue 2006-2, there are 720 locations showing a different IATA code.

Official UN/LOCODE tables UN/LOCODEs are released as a table. An individual revision is officially referred to as an "issue". A discussion of the table's structure follows.

Examples

Explanations

US NYC for New York City in the United States. Subdivision is the U.S. state of New York (see ISO 3166-2:US). Function: port, rail, road, airport, postal. IATA code is NYC. Coordinates: 40°42′N 074°00′W. DE BER for Berlin (city) in Germany. Subdivision is the German state of Berlin (see ISO 3166-2:DE). Function: port, rail, road, airport, postal. IATA code is BER. Coordinates: 52°31′N 013°23′E. DE TXL for Berlin-Tegel Airport in Germany. Function: airport. IATA code is TXL. FR PAR for Paris (city) in France. Subdivision is the French department of Paris (see ISO 3166-2:FR). Function: port, rail, road, postal. GB PAR for Par in United Kingdom. Subdivision is the English county of Cornwall (see ISO 3166-2:GB). Function: port. SE GOT for Göteborg (Goteborg without diacritics) in Sweden. Subdivision is the Swedish county of Västra Götaland (see ISO 3166-2:SE). Function: port, airport, postal. The IATA code of XWL indicated in the table is that of a train station in the city centre of Göteborg (though not the Central Station), while the IATA code for the main airport (Göteborg Landvetter Airport) is actually GOT. It also has a separate reference entry showing an alternate spelling of Gothenburg.

Data fields The fields are listed in the official order.

Ch (Changes) A change from the previous issue is indicated by one of the following characters in the first column: X Marked for deletion in the next issue # Change in location name (usually spelling) ¦ Other changes in the entry (not location) + Entry added to the current issue = Reference entry ! Retained for certain entries in the USA code list ("controlled duplications")

Locode The code is represented with a space between the alpha-2 codes of ISO 3166-1 country code and the 3-character element.

Name Names of locations should be shown using the 26 letters of the Roman alphabet with, where appropriate, diacritic signs as contained in ISO 10646-1/1993 or ISO 8859-1/1987.

Name Without Diacritics The name of the location, but non-practicable Diacritics may be ignored and should not be converted into additional characters(e.g., Göteborg may be read as Goteborg, rather than Goeteborg, Gothenburg, Gotembourg, etc.). Can contain an apostrophe, e.g. L'viv

SubDiv (Subdivision) The ISO 1 to 3 character alphabetic and/or numeric code for the administrative division (state, province, department, etc.) of the country, as included in ISO 3166-2/1998. Only the latter part of the complete ISO 3166-2 code element (after the hyphen) is shown.

Function Each defined function gets a classifier; the most important are: 1 = port (for any kind of waterborne transport) 2 = rail terminal 3 = road terminal 4 = airport 5 = postal exchange office 6 = Inland Clearance Depot – ICD or "Dry Port", "Inland Clearance Terminal", etc. 7 = fixed transport functions (e.g. oil platform)"; the classifier "7" is reserved for this function. Noting that the description "oil pipeline terminal" would be more relevant, and could be extended to cover also electric power lines and ropeway terminals. B = Border crossing function 0 = function not known, to be specified

Status Indicates the status of the entry by a 2-character code. The following codes are used at present: AA: Approved by competent national government agency AC: Approved by Customs Authority AF: Approved by national facilitation body AI: Code adopted by international organisation (IATA or ECLAC) AM: Approved by the UN/LOCODE Maintenance Agency AQ: Entry approved, functions not verified AS: Approved by national standardisation body RL: Recognised location - Existence and representation of location name confirmed by check against nominated gazetteer or other reference work RN: Request from credible national sources for locations in their own country RQ: Request under consideration UR: Entry included on user's request; not officially approved RR: Request rejected QQ: Original entry not verified since date indicated XX: Entry that will be removed from the next issue of UN/LOCODE

Date The date the location was added or updated: 0207 is July 2002, 9501 is January 1995, etc. The edition published in 2008 uses the value 0701 for additions, while in other cases the exact month is used like 9710, 0212.

IATA For correlation purposes, the IATA code for the location is marked if different from the second part of the UN/LOCODE.

Coordinates Some entries have coordinates in the database. They are represented as: ddmmN dddmmW, ddmmS dddmmE, etc.

Remarks The remarks column can among other things contain a hint to what specifically was changed (See data field - "Change").

… excerpt ends here. Continue reading the full article.

Worked examples

Example 1 — a first encounter with UN/LOCODE

Start with the simplest possible case. Write down what UN/LOCODE claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In science, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to UN/LOCODE before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about UN/LOCODE ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of UN/LOCODE

In research: UN/LOCODE appears in science research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry: Engineering practice reuses UN/LOCODE in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom: UN/LOCODE is common in secondary-school and first-year university syllabi. It links to neighbouring topics Country codes, Geocodes, UN/LOCODE, so understanding it makes those chapters shorter.
In everyday life: Look for UN/LOCODE outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

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How to study UN/LOCODE in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what UN/LOCODE means in your own words.
Compare your version with the excerpt and mark what you missed.
Work through the three examples above with pen and paper.
Explain UN/LOCODE out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is UN/LOCODE in simple terms?

Why does UN/LOCODE matter?

Because it connects several science ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study UN/LOCODE?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on UN/LOCODE.