science

Oblique Mercator projection

Oblique Mercator 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 Oblique Mercator projection rather than just read about it. In short: The oblique Mercator map projection is an adaptation of the standard Mercator projection. The oblique version is sometimes used in national mapping systems.

Key takeaways

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

Reference excerpt

The oblique Mercator map projection is an adaptation of the standard Mercator projection. The oblique version is sometimes used in national mapping systems. When paired with a suitable geodetic datum, the oblique Mercator delivers high accuracy in zones less than a few degrees in arbitrary directional extent.

Standard and oblique aspects

The oblique Mercator projection is the oblique aspect of the standard (or Normal) Mercator projection. They share the same underlying mathematical construction and consequently the oblique Mercator inherits many traits from the normal Mercator:

Both projections are cylindrical: for the normal Mercator, the axis of the cylinder coincides with the polar axis and the line of tangency with the equator. For the transverse Mercator, the axis of the cylinder lies in the equatorial plane, and the line of tangency is any chosen meridian, thereby designated the central meridian. Both projections may be modified to secant forms, which means the scale has been reduced so that the cylinder slices through the model globe. Both exist in spherical and ellipsoidal versions. Both projections are conformal, so that the point scale is independent of direction and local shapes are well preserved; Both projections can have constant scale on the line of tangency (the equator for the normal Mercator and the central meridian for the transverse). For the ellipsoidal form, several developments in use do not have constant scale along the line (which is a geodesic) of tangency. Since the standard great circle of the oblique Mercator can be chosen at will, it may be used to construct highly accurate maps (of narrow width) anywhere on the globe.

Spherical oblique Mercator In constructing a map on any projection, a sphere is normally chosen to model the Earth when the extent of the mapped region exceeds a few hundred kilometers in length in both dimensions. For maps of smaller regions, an ellipsoidal model must be chosen if greater accuracy is required; see next section.

Hotine oblique Mercator projection The Hotine oblique Mercator (also known as the rectified skew orthomorphic or 'RSO' projection) projection has approximately constant scale along the geodesic of conceptual tangency. Hotine's work was extended by Engels and Grafarend in 1995 to make the geodesic of conceptual tangency have true scale. The Hotine is the standard map projection used in Brunei, Malaysia, and Singapore. It was developed by Martin Hotine in the 1940s.

Space-oblique Mercator projection

The Space-oblique Mercator projection is a generalization of the oblique Mercator projection to incorporate time evolution of a satellite ground track.

See also List of map projections Mercator projection Transverse Mercator projection Space-oblique Mercator projection Scale (map)

References

External links

Illustrations

Worked examples

Example 1 — a first encounter with Oblique Mercator projection

Start with the simplest possible case. Write down what Oblique Mercator 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 Oblique Mercator 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 Oblique Mercator 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 Oblique Mercator projection

In research: Oblique Mercator 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 Oblique Mercator 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: Oblique Mercator projection is common in secondary-school and first-year university syllabi. It links to neighbouring topics Conformal projections, Geocodes, so understanding it makes those chapters shorter.
In everyday life: Look for Oblique Mercator 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 Oblique Mercator projection in 20 minutes

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

Frequently asked questions

What is Oblique Mercator projection in simple terms?

The oblique Mercator map projection is an adaptation of the standard Mercator projection. The oblique version is sometimes used in national mapping systems.

Why does Oblique Mercator 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 Oblique Mercator 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 Oblique Mercator projection.