science

Snyder equal-area projection

Snyder equal-area projection 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 Snyder equal-area projection rather than just read about it. In short: Snyder equal-area projection is a polyhedral map projection used in the ISEA (Icosahedral Snyder Equal Area) discrete global grids. It is named for John P.

Key takeaways

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

Reference excerpt

Snyder equal-area projection is a polyhedral map projection used in the ISEA (Icosahedral Snyder Equal Area) discrete global grids. It is named for John P. Snyder, who developed the projection in the 1990s. It is a modified Lambert azimuthal equal-area projection, most often applied to a polyhedral globe consisting of an icosahedron.

Use in the ISEA model As stated by Carr at al., page 32:

The S in ISEA refers to John P. Snyder. He came out of retirement specifically to address projection problems with the original EMAP grid (see Snyder, 1992). He developed the equal area projection that underlies the gridding system. ISEA grids are simple in concept. Begin with a Snyder Equal Area projection to a regular icosahedron (...) inscribed in a sphere. In each of the 20 equilateral triangle faces of the icosahedron inscribe a hexagon by dividing each triangle edge into thirds (...). Then project the hexagon back onto the sphere using the Inverse Snyder Icosahedral equal area projection. This yields a coarse-resolution equal area grid called the resolution 1 grid. It consists of 20 hexagons on the surface of the sphere and 12 pentagons centered on the 12 vertices of the icosahedron.

References

Illustrations

Snyder equal-area projection: With the dual tiling system is possible to transform the big triangular faces (gray) into small centered-hexagons (red), and vice versa. — With the dual tiling system is possible to transform the big triangular faces (gray) into small centered-hexagons (red), and vice versa.

Worked examples

Example 1 — a first encounter with Snyder equal-area projection

Start with the simplest possible case. Write down what Snyder equal-area projection 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 Snyder equal-area projection 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 Snyder equal-area projection 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 Snyder equal-area projection

In research: Snyder equal-area projection 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 Snyder equal-area projection 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: Snyder equal-area projection is common in secondary-school and first-year university syllabi. It links to neighbouring topics Cartography stubs, Equal-area projections, so understanding it makes those chapters shorter.
In everyday life: Look for Snyder equal-area projection 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 Snyder equal-area projection in 20 minutes

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

Frequently asked questions

What is Snyder equal-area projection in simple terms?

Snyder equal-area projection is a polyhedral map projection used in the ISEA (Icosahedral Snyder Equal Area) discrete global grids. It is named for John P.

Why does Snyder equal-area projection 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 Snyder equal-area projection?

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 Snyder equal-area projection.