Rainging and Offset - Introduction to Surveying - Surveying 1 | Summary and Q&A

TL;DR

This content discusses the different types of offsets and the methods of arranging in surveying, including perpendicular offset, oblique offset, long offset, short offset, direct ranging, and indirect ranging.

Key Insights

• 🧘 Offsets are linear measurements taken from a baseline to fix the position of objects in surveying.
• 🔺 Perpendicular offsets are right angle measurements, while oblique offsets are any other angle measurements.
• 😥 Direct ranging is used when station points are visible, while indirect ranging is used when there are obstacles between the points.
• 🤗 Different tools or techniques, such as swinging from a fixed point or using an open cross staff, can be used to establish perpendicular offsets.
• 😥 The establishment of intermediate points between station points is known as ranging. This can be done using direct methods or indirect methods depending on visibility.
• 🤒 Long offsets are greater than 15 feet, while short offsets are less than one chain meter.
• 🔺 Well-conditioned triangles have angles between 30 and 120 degrees and are used for oblique offsets.

Transcript

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Questions & Answers

Q: What are offsets used for in surveying?

Offsets are used to fix the positions of objects, such as trees or buildings, in relation to a baseline. They help in accurately plotting these objects on a survey map.

Q: What are the types of perpendicular offsets?

There are three methods for establishing a perpendicular offset: swinging from a fixed point, using an open cross staff, or using an optical square. Each method involves using different tools or techniques to create a right angle measurement.

Q: How do you establish an oblique offset?

To establish an oblique offset, you would take measurements at an angle other than 90 degrees from the baseline. The triangle formed by the baseline and the offset should have angles between 30 and 120 degrees.

Q: What is the difference between direct ranging and indirect ranging?

Direct ranging is used when the two station points are visible to each other, and it involves visually aligning the ranging rods. Indirect ranging is used when there are obstacles between the station points, and it involves establishing intermediate points using assistant surveyors.

Summary & Key Takeaways

• Offsets are linear measurements taken from a baseline to fix the position of objects, such as trees or buildings, on either side.

• There are two types of offsets: perpendicular and oblique. Perpendicular offsets are right angle measurements, while oblique offsets are any other angle measurements.

• Ranging is the process of establishing intermediate points between two station points. Direct ranging is used when the points are visible, while indirect ranging is used when there are obstacles between the points.