In a survey, A and B are two points. Already located with respect to A and B, point C is located by taking two readings, and then line CD is measured. The D is a point on AB. The line CD is known as

Question

Prepp Team · Accepted Answer

Understanding Survey Lines: Tie Lines, Base Lines, and Check Lines

In land surveying, various types of lines are used to establish control, locate points, and measure distances and angles. These lines form the framework of the survey.

Analyzing the Survey Scenario

The question describes a scenario where two main points, A and B, are already established. Point C is located relative to A and B using some measurements (readings). A line CD is then measured, where point D lies on the main line AB. We need to identify the type of line CD.

Points A and B can be considered part of a main survey line or base line.
Point C is an object or detail point being located.
Point D is located on the line AB.
The line CD connects the located point C to the main line AB.

Identifying the Line CD

Based on the description, the line CD serves to connect a point C (which has been located) to the main survey line AB. This is the definition of a tie line.

A tie line is a line that connects an object or a detail point to the main survey line. Its purpose is to fix the position of that point relative to the main survey traverse or base line.

Evaluating Other Options

Base line: A base line is a fundamental line in surveying from which the entire survey framework is built. It is usually the longest line and measured with high precision. Line CD connecting point C to AB is not the main framework line.
Check line: A check line is measured to verify the accuracy of other measurements or calculations in the survey. While CD provides a connection, its primary described function isn't solely for checking accuracy in this context; it's for locating point C.
Additional line: This is a very general term and not a specific, standard type of survey line used for locating points in this manner.

Therefore, the line CD, connecting the located point C to the line AB, is known as a tie line.

Revision Table: Types of Survey Lines

Type of Line	Purpose	Description in Scenario
Base Line	Main framework line for the survey.	A to B could represent part of a base line or main line.
Check Line	Verify accuracy of survey work.	Not explicitly described as being used for verification here.
Tie Line	Connect detail points to main survey lines.	Connects point C to the main line AB (at point D). Fits description.
Additional Line	General term, not a specific type.	Not a standard surveying term for this function.

Additional Information on Survey Lines

Understanding the different types of lines used in surveying is crucial for planning and executing accurate surveys. Each type serves a specific role in creating the survey network and locating features.

Base Lines: Provide the foundational measurements for triangulation or traversing. Accuracy in base line measurement is paramount.
Tie Lines: Essential for locating the positions of objects, boundaries, or other points that are not directly on the main survey lines. They 'tie' these points into the main survey control.
Check Lines: Also known as proof lines, they are used to detect errors and ensure the survey work closes within acceptable limits. They are independent measurements that verify the accuracy of other measured or calculated distances and angles.
Traverse Lines: Lines connecting a series of traverse stations, forming the main framework in traversing surveys.
Offset Lines: Short measurements taken perpendicular to a main survey line to locate details or features.

In the given problem, line CD acts as a tie line, connecting point C to the base line or main line AB, with D being the point on AB where the tie line meets.