Podcast
Questions and Answers
What is a back azimuth?
What is a back azimuth?
How is a back bearing related to a line's orientation?
How is a back bearing related to a line's orientation?
Which of the following statements is true regarding back azimuths?
Which of the following statements is true regarding back azimuths?
What is the main purpose of determining a back azimuth?
What is the main purpose of determining a back azimuth?
Signup and view all the answers
If the forward bearing of a line is 120 degrees, what is the back azimuth?
If the forward bearing of a line is 120 degrees, what is the back azimuth?
Signup and view all the answers
What is the main purpose of a Prismatic Compass?
What is the main purpose of a Prismatic Compass?
Signup and view all the answers
What other type of compass is mentioned alongside the Prismatic Compass?
What other type of compass is mentioned alongside the Prismatic Compass?
Signup and view all the answers
Which statement accurately reflects the types of compasses included in the collection?
Which statement accurately reflects the types of compasses included in the collection?
Signup and view all the answers
Which of the following is NOT a purpose of the Prismatic Compass?
Which of the following is NOT a purpose of the Prismatic Compass?
Signup and view all the answers
What is a feature that differentiates the Prismatic Compass from other compasses?
What is a feature that differentiates the Prismatic Compass from other compasses?
Signup and view all the answers
What is the back azimuth for an azimuth of 120°?
What is the back azimuth for an azimuth of 120°?
Signup and view all the answers
Which statement correctly describes the process to determine a back azimuth for an azimuth above 180°?
Which statement correctly describes the process to determine a back azimuth for an azimuth above 180°?
Signup and view all the answers
If the azimuth is 200°, what is the back azimuth?
If the azimuth is 200°, what is the back azimuth?
Signup and view all the answers
What is the correct definition of back azimuth?
What is the correct definition of back azimuth?
Signup and view all the answers
Which of the following azimuths would require subtracting 180° to find the back azimuth?
Which of the following azimuths would require subtracting 180° to find the back azimuth?
Signup and view all the answers
What are the three elements that determine an angle?
What are the three elements that determine an angle?
Signup and view all the answers
Which term describes the direction or orientation of an angle in relation to a reference line?
Which term describes the direction or orientation of an angle in relation to a reference line?
Signup and view all the answers
What is a reference meridian typically used for in angle measurement?
What is a reference meridian typically used for in angle measurement?
Signup and view all the answers
Which instrument is commonly used for measuring angles?
Which instrument is commonly used for measuring angles?
Signup and view all the answers
In the context of angle measurement, what is an azimuth angle?
In the context of angle measurement, what is an azimuth angle?
Signup and view all the answers
What is the correct format for writing a bearing?
What is the correct format for writing a bearing?
Signup and view all the answers
How is azimuth defined in relation to direction?
How is azimuth defined in relation to direction?
Signup and view all the answers
Which of the following best describes a bearing greater than 90º?
Which of the following best describes a bearing greater than 90º?
Signup and view all the answers
What is the significance of the letters N, S, E, and W in bearings?
What is the significance of the letters N, S, E, and W in bearings?
Signup and view all the answers
In the context of directional measurements, what does the term 'reference meridian' refer to?
In the context of directional measurements, what does the term 'reference meridian' refer to?
Signup and view all the answers
What is the significance of angle EAB in surveying?
What is the significance of angle EAB in surveying?
Signup and view all the answers
How can interior angles be improved in surveying?
How can interior angles be improved in surveying?
Signup and view all the answers
What does the term 'foresight' refer to in surveying?
What does the term 'foresight' refer to in surveying?
Signup and view all the answers
Which statement accurately describes the role of backsight in measuring angles?
Which statement accurately describes the role of backsight in measuring angles?
Signup and view all the answers
Why is averaging equal numbers of direct and reversed readings important?
Why is averaging equal numbers of direct and reversed readings important?
Signup and view all the answers
Study Notes
Angle Measurement
- Angles are defined as the difference in direction between two convergent lines.
- Horizontal angles are formed by the directions to two objects in a horizontal plane.
- Vertical angles are formed by two intersecting lines in a vertical plane, one being horizontal.
- Interior angles are measured inside a closed polygon, and their sum equals (n - 2) × 180°, where n is the number of angles.
- Exterior angles are located outside a closed polygon and are the supplement of interior angles. Their sum, plus the interior angles, equals 360°.
- Deflection angles are measured from an extension of the preceding course to the ahead line, either right (R) or left (L).
Direction of a Line
- Direction of a line is defined by the horizontal angle between the line and an arbitrarily chosen reference line (meridian).
- Geodetic meridian is a north-south reference line passing through Earth's geographic poles.
- Astronomic meridian passes through instantaneous position of Earth's geographic poles.
- Magnetic meridian is defined by a freely suspended magnetic needle, only affected by Earth's magnetic field.
- Grid meridian is used in surveys based on a coordinate system, parallel to geodetic north for a central meridian.
- Record meridian refers to directional references used in recorded documents from a previous survey.
- Assumed meridian is an arbitrarily assigned direction, often using a reference line.
Bearings and Azimuths
- Azimuths are horizontal angles measured clockwise from a reference meridian.
- In surveying, azimuths are usually observed from north.
- Bearings are another system for designating directions of lines, defining the acute horizontal angle between a reference meridian and the line, measured from north or south towards east or west.
- Bearings are less than 90° and use letters (N, S, E, W) to indicate the quadrant.
Comparison of Azimuths and Bearings
- Azimuths vary from 0° to 360°.
- Bearings vary from 0° to 90°.
- Azimuth requires only a numerical value.
- Bearings require two letters and a numerical value.
Back Azimuths and Back Bearings
- The back azimuth/bearing of a line is in the reverse direction of the forward azimuth/bearing.
- Back azimuth is calculated based on the forward azimuth:
- Adding 180° if forward azimuth is less than 180°, or
- Subtracting 180° if forward azimuth is greater than 180°.
- Back bearing is derived from the forward bearing by switching the first and second letters respectively (e.g., N to S, E to W).
Theodolite Survey
- Theodolites are surveying instruments used to measure horizontal and vertical angles.
- Theodolites work by combining optical plummets (or plumb bobs), a spirit level, and graduated circles.
- They can be classified as Optical-reading, Optical-reading repeating, Optical-reading directional, and Electronic-Digital.
Traverse
- A traverse is a series of consecutive lines whose lengths and directions are determined from observations.
- Closed traverses return to the starting point, forming a closed figure. Examples are polygon and link.
- Open traverses do not return to the starting point and need greater accuracy.
Angle Misclosure
- Angular misclosure is the difference between the observed angles and the geometrically correct total for a polygon traverse.
- Using (n-2)*180° for interior angles and (n+2)*180° for exterior angles where n is the number of sides.
Balancing Angles
- Angle balancing involves adjusting observed interior angles to match the geometric total of a closed traverse, using corrections based on poor observation conditions (if any).
- Two main methods are used: applying an average correction to all angles or making larger corrections to angles with poor observing conditions.
Departures and Latitudes
- Departures of a course are its orthographic projection along the east-west axis, and latitudes are its projection along the north-south axis.
- Calculated using the line's length and azimuth/bearing.
Coordinates
- Plane rectangular coordinate system.
- X-axis is east-west.
- Y-axis is north-south.
- Used to define the location of traverse stations.
Inversing
- Methods relate departures, latitudes, azimuths and bearings, enabling calculation of length and azimuth if departure and latitude are known.
Studying That Suits You
Use AI to generate personalized quizzes and flashcards to suit your learning preferences.
Related Documents
Description
Explore the principles of angle measurement and the direction of lines in this quiz. Delve into horizontal and vertical angles, as well as the concepts of interior and exterior angles in polygons. Test your knowledge on how angles are utilized in geodetic and astronomic contexts.
