science

Global Area Reference System

Global Area Reference System 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 Area Reference System rather than just read about it. In short: The Global Area Reference System (GARS) is a standardized geospatial reference system developed by the National Geospatial-Intelligence Agency (NGA) for use across the United States Department of Defense. Under the Chairman of the Joint Chiefs of Staff Instruction CJCSI 3900.01C dated 30 June 2007, GARS was adopted for use by the US DoD as "the “area-centric” counterpart to the “point-centric” MGRS".

Key takeaways

Global Area Reference System 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 Area Reference System to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of Global Area Reference System from memory before moving on to harder problems.

Reference excerpt

The Global Area Reference System (GARS) is a standardized geospatial reference system developed by the National Geospatial-Intelligence Agency (NGA) for use across the United States Department of Defense. Under the Chairman of the Joint Chiefs of Staff Instruction CJCSI 3900.01C dated 30 June 2007, GARS was adopted for use by the US DoD as "the “area-centric” counterpart to the “point-centric” MGRS". It uses the WGS 1984 Datum and is based on lines of longitude (LONG) and latitude (LAT). It is intended to provide an integrated common frame of reference for joint force situational awareness to facilitate air-to-ground coordination, deconfliction, integration, and synchronization. This area reference system provides a common language between the components and simplifies communications. GARS is primarily designed as a battlespace management tool and not to be used for navigation or targeting.

Design GARS divides the surface of the earth into 30-minute by 30-minute cells. Each cell is identified by a five-character designation. (ex. 006AG) The first three characters designate a 30-minute wide longitudinal band. Beginning with the 180-degree meridian and proceeding eastward, the bands are numbered from 001 to 720, so that 180 E to 179 30’W is band 001; 179 30’W to 179 00’W is band 002; and so on. The fourth and fifth characters designate a 30-minute wide latitudinal band. Beginning at the south pole and proceeding northward, the bands are lettered from AA to QZ (omitting I and O) so that 90 00’S to 89 30’S is band AA; 89 30’S to 89 00’S is band AB; and so on. Each 30-minute cell is divided into four 15-minute by 15-minute quadrants. The quadrants are numbered sequentially, from west to east, starting with the northernmost band. Specifically, the northwest quadrant is “1”; the northeast quadrant is “2”; the southwest quadrant is “3”; the southeast quadrant is “4”. Each quadrant is identified by a six-character designation. (ex. 006AG3) The first five characters comprise the 30-minute cell designation. The sixth character is the quadrant number. Each 15-minute quadrant is divided into nine 5-minute by 5-minute areas. The areas are numbered sequentially, from west to east, starting with the northernmost band. The graphical representation of a 15-minute quadrant with numbered 5-minute by 5-minute areas resembles a telephone keypad. Each 5-minute by 5-minute area, or keypad “key” is identified by a seven-character designation. The first six characters comprise the 15-minute quadrant designation. The seventh character is the keypad “key” number. (ex.006AG39)

See also Military Grid Reference System List of geodesic-geocoding systems

External links NGA's description Archived 2006-10-20 at the Wayback Machine Chairman of the Joint Chiefs of Staff Instruction CJCSI 3900.01C dated 30 June 2007

Illustrations

Worked examples

Example 1 — a first encounter with Global Area Reference System

Start with the simplest possible case. Write down what Global Area Reference System 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 Area Reference System 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 Area Reference System 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 Area Reference System

In research: Global Area Reference System 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 Area Reference System 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 Area Reference System is common in secondary-school and first-year university syllabi. It links to neighbouring topics Geographic coordinate systems, Military cartography, so understanding it makes those chapters shorter.
In everyday life: Look for Global Area Reference System 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 Area Reference System in 20 minutes

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

Frequently asked questions

What is Global Area Reference System in simple terms?

Why does Global Area Reference System 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 Area Reference System?

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 Area Reference System.