1.14.1 - Types of bearings
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Interactive Audio Lesson
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Whole Circle Bearing (WCB)
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Today, we’ll be learning about Whole Circle Bearing, or WCB. It's how we measure angles from magnetic north in a clockwise direction. Can anyone tell me what this means?
Does it mean all angles are measured from the north no matter which direction we're measuring?
Exactly! WCB gives us a complete circle of possible angles. It helps to simplify calculations. How many degrees can a whole circle contain?
Is it 360 degrees?
Correct! That's the full rotation. Remember, WCB values range from 0° to 360°. Let’s practice converting some angles now.
Reduced Bearing (RB)
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Now let’s discuss Reduced Bearing, or RB. Who can explain how this differs from WCB?
I think RB measures the angle from either the north or south using the smaller angle.
Great observation! It divides directions into quadrants, making it easier for smaller angles. Can someone name the four quadrants?
North-east, south-east, south-west, and north-west.
Exactly! And when measuring angles, we can denote them like N 30° E. This helps in determining the direction precisely. Any questions about how to convert WCB to RB?
Practical Applications of Bearings
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Understanding bearings is crucial in practical surveying applications. How do you think bearings help in land surveying?
They help in marking boundaries and directions to features on a map.
Exactly! And knowing the difference between WCB and RB allows us to choose the best system for our needs. Can anyone think of a situation where a specific bearing might be more useful?
I think in dense forests, using local landmarks for bearings could be more effective.
Good point! Usage of bearings improves navigation and understanding of land features. Let's summarize what we've learned today about bearings.
Introduction & Overview
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Quick Overview
Standard
The section details two primary types of bearings: Whole Circle Bearing (WCB) and Reduced Bearing (RB). WCB measures angles from a north reference point in a clockwise direction, while RB indicates angles either with respect to the north or south, depending on the smaller angle. Understanding these types is critical for accurate surveying.
Detailed
Types of Bearings
Bearings are essential in surveying, as they define the direction of survey lines in relation to a reference meridian. The two primary types of bearings are:
- Whole Circle Bearing (WCB): This method involves measuring the angle made by a survey line with the magnetic north direction, recorded in a clockwise fashion. Values range from 0° to 360°.
- Reduced Bearing (RB), also known as Quadrantal Bearing (QB): This type measures the angle in smaller sections based on a quadrant system, either to the west or east of the magnetic north or south, ensuring angles are less than 90°. The format may include designations such as N 30° 15’ E, or S 40° 23’ W.
Both methods play a pivotal role in navigation and land surveying, guiding professionals in accurately orienting maps, establishing boundaries, and plotting land features. Being familiar with these concepts is crucial for practical applications in various surveying scenarios.
Audio Book
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Introduction to Bearings
Chapter 1 of 4
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Chapter Content
Bearings are measured in two ways:
1. Whole circle bearing (WCB)
2. Reduced bearing (RB) or Quadrantal bearing (QB)
Detailed Explanation
Bearings are measurements used in surveying to indicate the direction of a survey line relative to a reference point. There are two primary methods of measuring bearings: Whole Circle Bearing (WCB) and Reduced Bearing (RB).
- Whole Circle Bearing (WCB): This is the angle made by a survey line with the magnetic north direction, measured in a clockwise direction ranging from 0° to 360°.
- Reduced Bearing (RB): Also known as Quadrantal Bearing (QB), this measures the angle made by the line with respect to the north or south direction, focusing on the smaller angle created. It divides the horizontal plane into four quadrants: NE, SE, SW, and NW.
Examples & Analogies
Imagine standing at a central location with four walkways leading out. If we refer to the walkway heading directly north, and measure the angles in relation to it for the other pathways, we'd essentially be describing the bearings. WCB gives us a complete 360° view, while RB simplifies directions into a more intuitive form using four quadrants.
Whole Circle Bearing (WCB)
Chapter 2 of 4
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Chapter Content
The whole circle bearing (WCB) of a survey line is the angle made by a survey line with the magnetic north direction, always measured in clockwise direction. It can have a value between 00 and 3600.
Detailed Explanation
The Whole Circle Bearing (WCB) is a universal way to define a direction by measuring the angle formed with the magnetic north. For example, if a survey line is oriented directly east, it would have a WCB of 90°. If it's oriented west, the WCB would be 270°. This method helps in making calculations straightforward, particularly in triangulation or calculations involving multiple survey lines.
Examples & Analogies
Consider a clock. The WCB is like telling the time—12 o'clock straight up (0°), 3 o'clock pointing to the right (90°), 6 o'clock downward (180°), and 9 o'clock to the left (270°). Just as you can tell time by where the hands are pointing, you can define direction using WCB.
Reduced Bearing (RB)
Chapter 3 of 4
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Chapter Content
The reduced bearing (RB) or quadrantal bearing (QB) of a line is the angle made by the line with the either magnetic north or south direction, whichever is a smaller angle.
Detailed Explanation
Reduced Bearings provide a more concise way to understand directions by focusing on the smallest angle to the north or south. The horizontal plane is divided into four quadrants; in the first and fourth quadrants (NE and NW), angles are measured towards the east or west from the north, whereas in the second and third quadrants (SE and SW), they are measured from the south. For example, an angle of 30° east from north would be written as N 30° E.
Examples & Analogies
Think of a compass needle, which tells you where north is. The RB is like giving someone simple directions: instead of saying 'head northeast' (WCB), you just say 'turn 30° right from north' (RB). It's about making it easier to communicate directions.
Quadrants and Reference Directions
Chapter 4 of 4
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Chapter Content
The north-south direction and the east-west direction divide the horizontal plane into four quadrants. Thus, in quadrants I and IV, the reference direction is north and the angle is measured either to the east or west. In quadrants II and III, the angle is measured from the south, either to the west or east.
Detailed Explanation
The concept of quadrants is crucial when using Reduced Bearings. The four quadrants are formed by the north-south and east-west lines intersecting:
1. Quadrant I: North and East (0° to 90°)
2. Quadrant II: South and East (90° to 180°)
3. Quadrant III: South and West (180° to 270°)
4. Quadrant IV: North and West (270° to 360°)
This division helps in clearly establishing a reference for bearings, facilitating easier navigation and surveying.
Examples & Analogies
Think of a map: if you draw an X from the north to south and east to west, you create a grid. Each section (or quadrant) of this grid helps you identify where to go based on simpler north/south and east/west directions. It’s like giving someone very easy directions based on where they stand.
Key Concepts
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Whole Circle Bearing (WCB): An angle measured clockwise from magnetic north, ranging from 0° to 360°.
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Reduced Bearing (RB): An angle measured from magnetic north or south in the smallest possible angle, aiding precise navigation.
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Quadrantal Bearing (QB): Another term for reduced bearing, indicating measurement relative to quadrants in navigation.
Examples & Applications
WCB Example: A line has a WCB of 90°, which aligns directly eastward from the magnetic north.
RB Example: If a line has an RB of N 45° E, it indicates it is 45° east from the magnetic north.
Memory Aids
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Rhymes
When you think of bearings, don't feel shy, North and south, give angles a try!
Stories
Imagine a sailor lost at sea, measuring angles with ease. He uses WCB to find his way, while RB helps him not to sway.
Memory Tools
Remember: WCB makes a full circle, RB keeps it simple – North or South, it’s all about the angle’s sample!
Acronyms
WCB
Whole Circle Bearing; RB
Flash Cards
Glossary
- Whole Circle Bearing (WCB)
The angle made by a survey line with the magnetic north, measured clockwise from 0° to 360°.
- Reduced Bearing (RB)
The angle made by a survey line with respect to the northern or southern direction, measured as the smaller angle from the nearest of these two.
- Quadrantal Bearing (QB)
Another name for reduced bearing, indicating angles based on the four quadrants formed around a reference point.
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