science

WOEID

WOEID 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 WOEID rather than just read about it. In short: A WOEID (Where On Earth IDentifier) is a unique 32-bit reference identifier, originally defined by GeoPlanet and now assigned by Yahoo!, that identifies any feature on Earth. In 2009, Yahoo! released GeoPlanet's WOEID data to the public, with the last release on 1 June 2012, after which Yahoo! decided to cease making the data downloadable until they "determine a better way to surface the data as a part of the servic…

Key takeaways

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

Reference excerpt

A WOEID (Where On Earth IDentifier) is a unique 32-bit reference identifier, originally defined by GeoPlanet and now assigned by Yahoo!, that identifies any feature on Earth. In 2009, Yahoo! released GeoPlanet's WOEID data to the public, with the last release on 1 June 2012, after which Yahoo! decided to cease making the data downloadable until they "determine a better way to surface the data as a part of the service". WOEIDs are used by a number of other projects, including Flickr, OpenStreetMap, Twitter, WOEID Search Engine (archive link) and Nations24. A successor to the WOEID project is Who's On First.

WOEID of some popular locations on Earth From WOEID Search Engine:

4118 - Toronto 44418 - London 615702 - Paris 2295019 - New Delhi 2295380 - Varanasi 2442047 - Los Angeles 2459115 - New York 2487956 - San Francisco 23424851 - Iran 29128560 - Kaithi

Example E.g. Berlin does not know about Germany, which itself doesn't know about Europe and so forth. GeoPlanet records, or places as they are called by Yahoo!, always (except one) have a reference to its parent place and therefore offer relations between places like the following:

Parent (direct surrounding place) Child (direct sub-places) Siblings (places sharing the same parent and place type) Ancestors (set of all parents) If you take e.g. our company's district you will get the following family tree:

Deutschland (WOEID 23424829) Bundesland Berlin (WOEID 2345496) Stadtkreis Berlin (WOEID 1259838) Berlin (WOEID 638242) Ortsteil Pankow (WOEID 26821868) Ortsteil Prenzlauer Berg (WOEID 26821872) Ortsteil Wedding (WOEID 26821851) Suan Luang (WOEID 12756344) ...

See also Discrete Global Grid List of geocoding systems

References

Worked examples

Example 1 — a first encounter with WOEID

Start with the simplest possible case. Write down what WOEID 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 WOEID 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 WOEID 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 WOEID

In research: WOEID 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 WOEID 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: WOEID is common in secondary-school and first-year university syllabi. It links to neighbouring topics Geocodes, Geographic object identifiers, so understanding it makes those chapters shorter.
In everyday life: Look for WOEID 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 WOEID in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what WOEID 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 WOEID out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is WOEID in simple terms?

Why does WOEID 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 WOEID?

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 WOEID.