Introduction

Topographic surveying is a fascinating field that combines the precision of science with the beauty of nature. It involves the detailed study of the earth’s surface, capturing both natural and man-made features. This article aims to provide an easy-to-understand overview of the instruments used in topographic surveying.

What is Topographic Surveying?

Topographic surveying, also known as land surveying, is an accurate representation of a specific area of interest, detailing both natural and man-made features. It includes properties, land features, and physical boundary details presented in a scaled survey drawing.

Evolution of Surveying

Surveying has a rich history that dates back to ancient civilizations and has evolved significantly over time. Here’s a brief overview of the evolution of surveying:

Ancient Times

The history of surveying dates back to ancient times, with a recorded land register in Egypt in 3000BC. The Egyptians used simple geometry and a tool known as a “gnomon” (an early form of sundial) to re-establish farmland boundaries annually after the flooding of the Nile. The Great Pyramid of Khufu at Giza, built about 2700 BCE, is a testament to the ancient Egyptians’ command of surveying.

Roman Era

Under the Romans, land surveying was established as a profession and land surveyors established the basic measurements under which the Roman Empire was divided. They also created a tax register of conquered lands around 300AD.

18th Century Europe

In eighteenth-century Europe, a method of surveying known as triangulation, which relied on the measurement of angles, was used to build a hierarchy of networks to allow point positioning within a country.

British Colonization of Australia and New Zealand

During the early days of British colonization of Australia and New Zealand, much of the survey work was carried out using Gunter’s chains, measuring wheels, circumferenter, Kater’s compass, and even pacing.

Modern Times

Over time, Gunter’s chain was replaced by steel bands and invar tapes, and later by Electromagnetic Distance Measurement (EDM) equipment, and subsequently Global Positioning System (GPS) devices. Likewise, compasses were replaced by transits, later theodolites, and then Total Stations, which combined angular and distance measurement in a single survey instrument.

Why is Topographic Surveying Important?

Topographic surveys are essential for land development projects as they help to correctly plan out and coordinate proposed layouts. Accurate land measurements allow you to see how the existing site is arranged, including the height of items.

Importance of Surveying

1. Planning and Designing: Surveying is the first step in any engineering project, be it the construction of a building, a road, a bridge, or a dam. The planning and design of all these projects are based on surveying measurements.
2. Execution of Projects: During the execution of any project, construction is carried out along the lines and points established by surveying. This ensures that the project is built exactly as it was designed.
3. Land Measurement and Boundary Fixation: The measurement of land and the fixation of its boundaries cannot be done without surveying. This is crucial for property transactions such as buying, selling, mortgaging, and leasing.

Instruments Used in Topographic Surveying

Topographic surveys are undertaken using a range of different survey equipment which measure distances and angles extremely accurately. Here are some of the key instruments used:

Total Station

A total station is an electronic theodolite combined with an electronic distance meter. It measures angles and distances very precisely, helping to produce a CAD (computer-aided design) drawing which accurately details the surveyed points.

GPS Technology

Global Positioning System (GPS) technology is a game-changer in topographic surveys. Surveyors use precise GPS equipment when surveying an area to help locate and position fixed points of an area of land.

Laser Scanners

Laser scanners are used to create highly detailed 3D models of the land. They capture a wide range of information which can be used to produce drawings.

Aerial Photography

Aerial photography, often captured using drones, provides a bird’s eye view of the land. This imagery can be particularly useful for large-scale surveys.

Recent Technological Advancements in Surveying

1. Unmanned Aerial Vehicles (UAVs): Also known as drones, UAVs are increasingly being used in surveying for capturing high-resolution images and videos of the land. They can cover large areas quickly and efficiently, making them ideal for topographic surveys.
2. 3D Laser Scanning: This technology uses lasers to capture detailed measurements of high-density areas in a short amount of time. The data collected can be used to create detailed 3D models.
3. Robotic Total Stations: These devices can operate autonomously, allowing for increased efficiency and accuracy in data collection. They can be remotely controlled, reducing the need for manual operation.
4. GPS Technology: The use of GPS in surveying has become more precise and reliable. It allows for real-time data collection and instant processing.
5. Digital Terrestrial Photogrammetry: This involves taking measurements from photographs, especially for recovering the exact positions of surface points.
6. Remote Sensing Satellites (LiDAR): Light Detection and Ranging (LiDAR) uses light in the form of a pulsed laser to measure variable distances to the Earth. These light pulses—combined with other data recorded by the airborne system— generate precise, three-dimensional information about the shape of the Earth and its surface characteristics.
7. Use of Drones or Unmanned Aerial Vehicles (UAV): Drones are being increasingly used for aerial surveys. They can capture high-resolution images and are capable of covering large areas in a short amount of time.
8. Mobile 3D Mapping Techniques: These techniques involve the use of mobile devices to capture 3D data of the environment.
9. Cloud Computing in Data Storage for Surveying: Cloud computing allows for the storage and access of large amounts of data, which is particularly useful in surveying where large datasets are common.

Conclusion

Topographic surveying is a crucial aspect of land development projects, conservation efforts, and historical records. The instruments used in topographic surveying, such as total stations, GPS technology, laser scanners, and aerial photography, ensure the accuracy and precision of these surveys.

Keywords: Topographic Surveying, Total Station, GPS Technology, Laser Scanners, Aerial Photography, Land Development, Conservation, Historical Records, Architecture Students