astronomy

Universal polar stereographic coordinate system

Universal polar stereographic coordinate system is a astronomy 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 Universal polar stereographic coordinate system rather than just read about it. In short: The universal polar stereographic (UPS) projected coordinate system is based on a conformal map projection of the Earth spheroid. It is used in conjunction with the universal transverse Mercator (UTM) coordinate system to locate positions on the surface of the Earth.

Key takeaways

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

Reference excerpt

The universal polar stereographic (UPS) projected coordinate system is based on a conformal map projection of the Earth spheroid. It is used in conjunction with the universal transverse Mercator (UTM) coordinate system to locate positions on the surface of the Earth. UPS covers the Earth's polar regions, specifically the areas north of 84°N and south of 80°S, which are not covered by the UTM grids, plus an additional 30 minutes of latitude extending into UTM grid to provide some overlap between the two systems. In the polar regions, directions can become complicated, with all geographic north–south lines converging at the poles. The difference between UPS grid north and true north can therefore be anything up to 180°—in some places, grid north is true south, and vice versa. UPS grid north is arbitrarily defined as being along the prime meridian in the Antarctic and the 180th meridian in the Arctic; thus, east and west on the grids when moving directly away from the pole are along the 90°E and 90°W meridians respectively.

Projection system As the name indicates the UPS system uses a stereographic map projection, specifically a secant version based on an elliptical model of the earth. The scale factor at each pole is adjusted to 0.994 so that the latitude of true scale is 81.11451786859362545° (about 81° 06' 52.3") North and South. The scale factor inside the regions at latitudes higher than this parallel is too small, whereas the regions at latitudes below this line have scale factors that are too large, reaching 1.0016 at 80° latitude. The scale factor at the origin (the poles) is adjusted to minimize the overall distortion of scale within the mapped region. As with the Mercator projection, the region near the tangent (or secant) point on a Stereographic map remains very close to true scale for an angular distance of a few degrees. In the ellipsoidal model, a stereographic projection tangent to the pole has a scale factor of less than 1.003 at 84° latitude and 1.008 at 80° latitude. The adjustment of the scale factor in the UPS projection reduces the average scale distortion over the entire zone.

References Snyder, John P. (1987). Map Projections – A Working Manual. U.S. Geological Survey Professional Paper 1395. United States Government Printing Office, Washington, D.C. Defense Mapping Agency Technical Manual 8358.1 Datums, Ellipsoids, Grids, and Grid Reference Systems (PDF). Defense Mapping Agency. 1990. Retrieved 11 June 2024. Defense Mapping Agency Technical Manual 8358.2: The Universal Grids: Universal Transverse Mercator (UTM) and Universal Polar Stereographic (UPS) (PDF). Defense Mapping Agency. 18 September 1989. Retrieved 11 June 2024.

External links

National Geospatial-Intelligence Agency, Geospatial Sciences Publications GeographicLib provides a utility GeoConvert (with source code) for conversions between geographic, UTM, UPS, and MGRS. Here is an online version of GeoConvert.

Illustrations

Worked examples

Example 1 — a first encounter with Universal polar stereographic coordinate system

Start with the simplest possible case. Write down what Universal polar stereographic coordinate system claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In astronomy, 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 Universal polar stereographic coordinate 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 Universal polar stereographic coordinate 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 Universal polar stereographic coordinate system

In research: Universal polar stereographic coordinate system appears in astronomy 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 Universal polar stereographic coordinate 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: Universal polar stereographic coordinate system is common in secondary-school and first-year university syllabi. It links to neighbouring topics Geographic coordinate systems, so understanding it makes those chapters shorter.
In everyday life: Look for Universal polar stereographic coordinate 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.

Ask Teacher Smith questions about this articleOpens your AI tutor with a question about “Universal polar stereographic coordinate system” →

Affiliate

Preply — study more efficiently by working with a personal tutor. 50% off.

How to study Universal polar stereographic coordinate system in 20 minutes

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

Frequently asked questions

What is Universal polar stereographic coordinate system in simple terms?

Why does Universal polar stereographic coordinate system matter?

Because it connects several astronomy 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 Universal polar stereographic coordinate 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 Universal polar stereographic coordinate system.