Table of Contents
What Are Arrows In Surveying?
Arrows are widely used as marking pins in chain surveying, serving a critical role in measuring linear distances and indicating the end of a chain length. They are invaluable tools employed by surveyors to establish a series of points on a surface and accurately measure distances. Arrows can be constructed using different materials such as wood, steel, or fiberglass-reinforced concrete, with each material offering distinct advantages based on the intended task and environmental conditions.
In chain surveying, where the length of the line to be measured exceeds the length of a chain, arrows are placed at the end of each chain length. The arrows can be either bare, made from wood and steel, or constructed from fiberglass-reinforced concrete, which is preferred for its superior strength. If the ground is particularly hard and tough, a scratch may be made with the pointed end of the arrow to indicate the end of the chain length.
Arrows used in surveying typically have a minimum tensile strength of 700 N/mm2 and a diameter of 4 mm. The length of arrows can range from 250 to 500 mm, with an overall length of 400 mm and a 50 mm diameter loop. To enhance visibility, white or red tape is often affixed to the ring of the arrows, making them easily identifiable in the field.
These versatile tools find application in various surveying tasks, including measuring horizontal distances and establishing a series of points on a surface. Additionally, arrows serve as alignment indicators, aiding surveyors in maintaining the correct orientation and direction while traversing the survey area.
Types Of Arrows In Surveying
1. Wooden Arrows:
Wooden arrows are good for marking things because they are cheap and easy to make special. You can paint them or write on them with special information for the surveyor. They are used to mark things temporarily or show where the boundaries are. They are simple and easy to use!
2. Metal Arrows:
Metal arrows are really strong and last a long time. They are made of special stuff like aluminum or stainless steel. People use metal arrows when they want to mark things for a long time or when they need to see them for a long time. They are tough and stay visible!
3. Fiberglass Arrows:
Fiberglass arrows are in the middle. They are not too expensive and not too weak. They are light and don’t break easily. They can handle different weather, too. People use fiberglass arrows when they need to mark points in buildings or when they are doing surveys. They are tough but not too expensive!
4. Plastic Arrows:
Plastic arrows are light and not too expensive. They are good when you need to mark things temporarily or when you don’t want to spend a lot of money. They are colorful and easy to see. Plastic arrows are used when you only need markers for a short time or when you don’t want to spend too much money.
5. Reflective Arrows:
Reflective arrows are special because they shine in the dark or when there isn’t much light. They have shiny stuff on them. People use them to mark things or show directions when it’s hard to see. Reflective arrows are great for keeping things visible and safe in the dark.
Uses Of Arrows In Surveying
1. Boundary Measurement:
Arrows are used to measure and draw boundaries. They help establish a series of points that can be used for surveying, coordinate measurements, or triangulation.
2. Distance Measurement:
The distance between two points can be determined by using arrows placed on the ground. Surveyors can measure the distance by counting the number of arrows between the points.
3. Location Determination:
Arrows marked on the surface with a target length can be used to determine the location of the target. Surveyors can align their instruments with the arrows to pinpoint the desired location accurately.
4. Chain-Transverse Measurements:
Arrays of points can be found and measured using a chain-transverse unit, which is approximately equivalent to an arrow-unit. This technique helps surveyors measure and map out a series of points on the ground.
5. Linear Distance Measurement:
Surveyors use arrows to measure linear distances. By placing arrows at specific intervals along the desired path, they can measure the length of the line accurately.
6. Marker Placement:
Arrows, particularly those made from wood, steel, or fiberglass reinforced concrete, are placed in the ground to mark the end of each chain length. These arrows may also be used to scratch the ground in case it is hard or tough.
7. Standard Specifications:
Arrows used in surveying generally follow specific standards. The overall length of arrows is typically 400mm, with a 50mm diameter loop, as per IS 1842 (Indian Standard). To enhance visibility, white or red tape is often affixed to the arrow’s ring.
8. Visibility Enhancement:
The visibility of arrows can be improved by attaching white or red tape to the ring. This ensures that surveyors can easily spot and align their instruments with the arrows.
9. Adaptability to Applications:
The length and width of arrows can vary depending on the specific surveying application. Different sizes of arrows may be used to accommodate varying measurement requirements or specific field conditions.
10. Alignment Indicators:
Arrows serve as alignment indicators in surveying. They provide visual references that help surveyors align their instruments and maintain accurate measurements during various surveying tasks.
Faqs
Arrows or pins help us mark the ends of a line we measure. They show us where the line stops, so we can measure accurately. We put them in the ground at the end points.
We use arrows or pins to make sure our measurements are right. They help us see the end points clearly and keep our surveying accurate. We can also use them later to show where things should be built or mapped.
We use different types of arrows or pins. Some are made of wood, and others are made of metal. The wooden ones are for short surveys, and the metal ones are for longer surveys. It depends on how long we need them to last.
To put arrows or pins in, we do these steps: a. First, we clear the ground and remove anything in the way. b. Then, we use special tools to find the ends of the line we’re measuring. c. We push or hammer the arrows or pins into the ground at those end points. We make sure they stand straight up. d. We check if the arrows or pins are in the right place and stay strong before we keep measuring.
Usually, we can use arrows or pins again for other surveys. But it depends on what they’re made of and how they look. Wooden ones might not last as long, but metal ones can be used many times. We always check them before each survey to make sure they work well.