science

Gila and Salt River meridian

Gila and Salt River meridian 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 Gila and Salt River meridian rather than just read about it. In short: The Gila and Salt River Meridian intersects the initial point on the south side of the Gila River, opposite the mouth of Salt River, at latitude 33° 22′ 37.82733″ north, longitude 112° 18′ 21.99931″ west from Greenwich based on NAD 83, and governs the surveys in the territory of Arizona. The current declination for the initial point is 12° east.

Key takeaways

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

Reference excerpt

The Gila and Salt River Meridian intersects the initial point on the south side of the Gila River, opposite the mouth of Salt River, at latitude 33° 22′ 37.82733″ north, longitude 112° 18′ 21.99931″ west from Greenwich based on NAD 83, and governs the surveys in the territory of Arizona. The current declination for the initial point is 12° east. It is located on Monument Hill, an easily visible hill just south of the confluence of the Gila and Salt Rivers, in Avondale, Arizona, about 14 miles (23 kilometers) southwest of downtown Phoenix. The original marker was set in 1851 by John R. Bartlett. In 1934, the U.S. Coast and Geodetic Survey set triangulation station "INITIAL" approximately 15 feet from the initial point. Ty White, Associate Cadastral Engineer for the U.S. Bureau of Land Management (BLM), re-monumented the initial point on December 1, 1944. On April 24,1962, the monument was re-established by Leonard W. Murphy, based on the Ty White's field notes, because the previous monument had been vandalized. On April 26, 1984, Paul L. Reeves and John P. Bennet re-monumented the original corner. On February 19, 2006, the initial point was again re-monumented due to deterioration of the 1985 plaque. This re-monumentation was performed by staff from the BLM, members of the Arizona Professional Surveyors Society, and students at Phoenix College. The initial point was added to the National Register of Historic Places (listing #02001137) as of October 15, 2002. The plaque for that listing was installed as part of the 2006 re-monumenting. For the 1984/2006 marker, handheld GPS units give a reading of 33° 22.631′ N latitude and 112° 18.366′ W longitude due to the specific geoid used. The angle between the 1984/2006 marker and the 1931 marker is at an azimuth bearing of 292°, a.k.a. 68° west of due north. The location is immediately east of Phoenix Raceway (formerly Phoenix International Raceway) and the western side of Monument Hill is terraced for low-priced race viewing.

See also Baseline Road (Arizona) List of principal and guide meridians and base lines of the United States

References Raymond, William Galt (1914). Plane Surveying for Use in the Classroom and Field (via Internet Archive). New York: American Book Company.

Further reading "History of Arizona, Vol. IV, Chapter XVI. Early Surveys". The University of Arizona Library. Retrieved 2012-09-24.

External links "Gila and Salt River Meridian, Avondale, AZ". Principal Meridian Project. Retrieved 2012-09-24. "Cadastral Survey: Gila and Salt River Meridian". U.S. Bureau of Land Management. Archived from the original on 2011-12-10. Retrieved 2012-09-24. "Gila and Salt River Meridian". The Center for Land Use Interpretation. Retrieved 2012-09-24. "Arizona's Initial Point". Arizona Professional Land Surveyors. Archived from the original on 2012-12-02. Retrieved 2012-09-24. "Initial Point of the Gila and Salt River Base Line and Meridian - Avondale, AZ". Waymarking.com. Retrieved 2012-09-24. U.S. Geological Survey Geographic Names Information System: Initial Point

Illustrations

Worked examples

Example 1 — a first encounter with Gila and Salt River meridian

Start with the simplest possible case. Write down what Gila and Salt River meridian 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 Gila and Salt River meridian 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 Gila and Salt River meridian 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 Gila and Salt River meridian

In research: Gila and Salt River meridian 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 Gila and Salt River meridian 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: Gila and Salt River meridian is common in secondary-school and first-year university syllabi. It links to neighbouring topics Geography of Arizona, Historic surveying landmarks in the United States, Meridians and base lines of the United States, so understanding it makes those chapters shorter.
In everyday life: Look for Gila and Salt River meridian 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 Gila and Salt River meridian in 20 minutes

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

Frequently asked questions

What is Gila and Salt River meridian in simple terms?

Why does Gila and Salt River meridian 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 Gila and Salt River meridian?

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 Gila and Salt River meridian.