science

Initial point

Initial point 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 Initial point rather than just read about it. In short: In surveying, an initial point is a datum (a specific point on the surface of the earth) that marks the beginning point for a cadastral survey. The initial point establishes a local geographic coordinate system for the surveys that refer to that point.

Key takeaways

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

Reference excerpt

In surveying, an initial point is a datum (a specific point on the surface of the earth) that marks the beginning point for a cadastral survey. The initial point establishes a local geographic coordinate system for the surveys that refer to that point. An initial point is defined by the intersection of a principal meridian and a base line.

Selection of initial points

A principal meridian and base line are usually established based on a preselected initial point, often some distinct geographical feature. As an example, the first established initial point in California was the Mount Diablo meridian. It was chosen because the summit of Mount Diablo could be seen for many miles around and could be referenced for surveys. In other cases, a meridian and a base line were chosen separately based on other geographical features. For example, the Fifth principal meridian in the new Louisiana Purchase was established in 1815, with its southern end based on the confluence of the Arkansas and Mississippi Rivers, and extended northward from that point. The eastern end of the base line was chosen as the confluence of the St. Francis and Mississippi Rivers and extended westward. The initial point would be established where the meridian and the base line crossed, which turned out to be in the middle of a swamp in eastern Arkansas. This point is now located in the Louisiana Purchase State Park. Some initial points were chosen based on existing markers. The initial point for the Gila and Salt River meridian was established based on an existing marker that had been set up in 1851 to mark a point on the Mexico–United States border before the Gadsden Purchase. Many of the initial points in the United States have been listed on the National Register of Historic Places. Notable initial points include:

Beginning Point of the U.S. Public Land Survey Initial Point (Oklahoma) Initial Point of Boundary Between U.S. and Mexico, California Initial Point of the Gila and Salt River Base Line and Meridian, Arizona Mason and Dixon Survey Terminal Point, West Virginia

See also Public Land Survey System List of principal and guide meridians and base lines of the United States

References

External links C. A. White. "A History of the Rectangular Survey System" (PDF) (This is a large file, approximately 46MB. Searchable PDF.). U.S. Bureau of Land Management. Archived from the original (PDF) on 2008-10-10. Retrieved 2012-10-09. "Cadastral Survey". U.S. Bureau of Land Management. Archived from the original on 2012-10-06. Retrieved 2012-10-09.

Illustrations

Worked examples

Example 1 — a first encounter with Initial point

Start with the simplest possible case. Write down what Initial point 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 Initial point 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 Initial point 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 Initial point

In research: Initial point 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 Initial point 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: Initial point is common in secondary-school and first-year university syllabi. It links to neighbouring topics Initial points, so understanding it makes those chapters shorter.
In everyday life: Look for Initial point 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 Initial point in 20 minutes

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

Frequently asked questions

What is Initial point in simple terms?

Why does Initial point 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 Initial point?

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 Initial point.