Control Networks in Surveying: Everything You Need to Know
Accurate surveying provides unrivalled information about land and the environment, which is critical for successful construction projects and map-making. However, it’s vital that steps are taken to ensure complete accuracy of a survey, and this is where control networks come into play.
In this article, we take a closer look at the different types of control networks in surveying and explain how these networks are used to optimise the quality and accuracy of surveys. Read on to get a better understanding of the benefits control networks in surveying can offer.
How Are Control Networks Used in Surveying?
Before a primary survey is undertaken, a control network is set up across the relevant land. This typically consists of survey stations, which are strategically placed across the area. Once in situ, these survey stations provide vital reference points for subsequent surveying activities.
From a survey station, accurate distances and angles can be measured, for example, and the control network provides consistency and reliability when mapping grid lines, benchmarks and construction elements.
Different Types of Control Networks in Surveying
Before embarking on a project, it’s important to understand the difference types of control networks in surveying. Then, you can make an informed decision about which control network is most suited to your needs. In general, there are two types of control networks used in surveying:
- Horizontal Control Survey
- Vertical Control Survey
Horizontal Control Surveys
When you need to measure points across a horizontal plane, this is the type of control survey to use. Essential for map-making, horizontal control surveys are also commonly used prior to full engineering surveys being carried out.
As part of the horizontal control survey process, a surveyor will map the control points and measure angles and distances between them to provide accurate and reliable data.
Vertical Control Surveys
If you need to know the elevation of an area, a vertical control survey can provide the information you’re looking for. By establishing control points and then measuring their elevation, a professional surveyor can collate critical data that is routinely used when creating topographical surveys or undertaking a civil engineering project.
Primary and Secondary Controls
When talking about the different types of control networks in surveying, you may also come across the terms ‘primary controls’ and ‘secondary controls’. Primary controls are the established control points that are initially mapped and used throughout an entire project, while secondary controls are mapped from primary points and may be used throughout certain phases of a construction project.
Conducting a Control Survey
As well as knowing the different types of control networks in surveying, it can be advantageous to know how these surveys are carried out and what processes are used to ensure optimal accuracy. Here, we provide a brief run-through of the steps usually taken when conducting a control network survey:
1. Information Gathering
Once an area of interest has been identified, the first step in the control network survey process is undertaking reconnaissance to gather relevant information. Existing landmarks, the type of terrain and features of the land are all used to inform the planning process, which is why information gathering is such an important step when conducting a control survey.
2. Distance Measuring
As you might expect, measuring the distance between two points is a core element of a control survey and various tools can be used to facilitate this. Rangefinders, GPS devices, 3D scanners and even drones are commonly used for distance measuring, so you can be confident that the data generated will be entirely accurate.
3. Direction Establishment
To establish the direction of the line of sight or the survey line, the angles between two points can be measured and analysed. Alternatively, a compass can be used to confirm the direction.
4. Position Location
As part of the control network surveying process, it’s important to map specific locations. Again, specialist equipment and methodologies are used to ensure the accuracy of the information that’s generated. For example, a surveyor may use a total station or GPS device to determine the angles between a third point and two established points to map the position of the third point.
5. Data Gathering with a Total Station
A total station enables surveyors to gather and record accurate data, which is why they are commonly used in control surveys. As the location of numerous points are recorded, data is collated that begins to reflect the area of the interest and its environment.
Benefits of Control Networks in Surveying
Now you have a clear understanding of the types of control networks in surveying, you’ll probably want to know whether they’re a critical element of your project. If so, take a look at the benefits control networks can offer:
Increased Accuracy
First and foremost, establishing a control network enhances the accuracy of subsequent surveys and improves the accuracy of the construction project itself. As a control survey is typically carried out ahead of any other types of surveys, it maximises the efficacy of future surveying activities by providing an accurate and reliable source of data. As a result, you’ll have increased confidence that the measurements used throughout your project will be accurate and dependable.
Enhanced Efficiency
Having a control survey undertaken allows you to operate with increased efficiency throughout the remainder of the project. With control data to rely on, subsequent surveys and the construction project can be carried out more quickly, thus increasing efficiency and allowing you to meet critical deadlines with ease.
Reduced Costs
Any mistakes that occur during a construction project can have costly consequences. If just one measurement is incorrect, it could lead to months of delays and millions of pounds of losses, which is why it’s so important to ensure that professional control networks are used to access accurate data, protect the project, reduce potential losses.
Arrange Professional Surveys with Geo Cart
To find out more or to talk to use about setting up survey control networks, contact our experienced team now on 07397 223 267 or email us at office@www.geocart.co.uk