science

Global Administrative Unit Layers

Global Administrative Unit Layers 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 Global Administrative Unit Layers rather than just read about it. In short: The Global Administrative Unit Layers (GAUL) is a spatial database of the administrative units for all the countries in the world. It is a project of the Food and Agriculture Organization (FAO) of the United Nations.

Key takeaways

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

Reference excerpt

The Global Administrative Unit Layers (GAUL) is a spatial database of the administrative units for all the countries in the world. It is a project of the Food and Agriculture Organization (FAO) of the United Nations.

Mission The GAUL aims at compiling and disseminating the most reliable geographic information on administrative units for all the countries in the world, thereby contributing to the standardization of the spatial dataset representing administrative units. In this framework, its purposes are:

to overcome the fragmentation of the global dataset occurring when administrative units layers are digitized on a country-by-country basis to keep historical track of changes occurring on the shapes and extent of the administrative units to promote a unified coding system that reduces maintenance efforts.

Characteristics The GAUL always maintains global geographic layers (in shapefile format) with a unified coding system at the levels of country, first administrative (e.g. regions), and second administrative (e.g. districts). In addition, when data is available, it provides layers on a country-by-country basis down to third, fourth and lower levels. The target beneficiary of the GAUL data is the UN community, universities, and other authorized international and national institutions/agencies. Data might not be officially validated by authoritative national sources and can not be distributed to the general public. A disclaimer should always accompany any use of the GAUL data. Because the GAUL works at global level, controversial boundaries can not be ignored. The approach of the GAUL is to maintain disputed areas in such a way to preserve national integrity for all disputing countries. The coastline of the GAUL is mostly compliant with the coast of the International Boundary map delivered by the UN Cartographic Section except for some countries (e.g. Vietnam, India, Bangladesh, etc.) where it has been updated according to the satellite images (e.g. Landsat ETM). For future releases of the GAUL, the process of updating the coastline will go on, country by country, through a comparison with the satellite images. The GAUL keeps track of administrative units that have been changed, added, or deleted in the past. Changes implemented in different years are recorded in the GAUL on different layers. For this reason the GAUL product is not a single layer but a group of layers, named the GAUL Set. The GAUL project does not implement changes dated before 1990. GAUL codes are numeric and unique for all administrative units at any of the administrative hierarchical level. Any GAUL code is independent from the codes of its higher administrative levels. GAUL codes assigned to administrative units of a given country are not necessarily sequential numbers. The main benefit of the GAUL Coding System is that changing in the codes of an administrative unit might not imply a change of codes of the correspondent units at lower levels. This means that the effort to maintain the links between thematic data and associated administrative units is reduced to a minimum.

Organization The implementation of the GAUL initiative is based on a collaborative work among international agencies and national authorities generating and collecting spatial information on administrative units. The role of FAO is to keep this network of collaborators active, to evaluate and compile data from available sources, to establish procedures for data integration, to generate the GAUL codes and periodically to disseminate the GAUL Set. The overall methodology consists in:

collecting the best available data from most reliable sources establishing validation periods of the geographic features (when possible) adding selected data to the global layer based on the international boundaries provided by the UN Cartographic Unit generating codes using the GAUL Coding System distributing data to the users The GAUL has a consistent framework for the delivery of the data. Once a year, an updated version of the GAUL set is released through Geonetwork Archived 2008-12-01 at the Wayback Machine. A new version includes all updates made in the course of the previous year. The dataset is free of charge and it can be downloaded by login (to receive an account, just send an email to the contacts listed at the bottom of this article). The new version GAUL 2009 will be available on Geonetwork from January 2009.

External links FAO GeoNetwork Archived 2010-03-03 at the Wayback Machine

Worked examples

Example 1 — a first encounter with Global Administrative Unit Layers

Start with the simplest possible case. Write down what Global Administrative Unit Layers 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 Global Administrative Unit Layers 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 Global Administrative Unit Layers 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 Global Administrative Unit Layers

In research: Global Administrative Unit Layers 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 Global Administrative Unit Layers 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: Global Administrative Unit Layers is common in secondary-school and first-year university syllabi. It links to neighbouring topics Human geography, so understanding it makes those chapters shorter.
In everyday life: Look for Global Administrative Unit Layers 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 Global Administrative Unit Layers in 20 minutes

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

Frequently asked questions

What is Global Administrative Unit Layers in simple terms?

Why does Global Administrative Unit Layers 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 Global Administrative Unit Layers?

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 Global Administrative Unit Layers.