Curves in surveying - What is it, Its types, and Advantages

In this article, we will see about what is curve in surveying, its types, purposes, its elements, advantages and more.

What is curves in surveying?

Curves surveying is the process of measuring and mapping the curvature of roads, rivers, and other natural features on a piece of land. 

This involves the use of mathematical calculations and specialized tools, such as total stations, theodolites, and GPS equipment, to accurately measure angles, distances, and elevations. 

The data collected is then used to create detailed maps and plans of the area being surveyed.

Types of curves

There are two types of Curves.

1. Horizontal Curve

2. Vertical curve

Surveyors use horizontal and vertical curves to calculate the radius and slope of a feature. 

Horizontal curves are used to calculate the radius of a curve and the central angle. While vertical curves are used to calculate the grade or slope of a road or other feature. 

This information is used to ensure that the design of the road or other feature is safe and efficient.

Additionally, surveyors also take into account the super elevation of the road when surveying curves.

Super elevation is the amount by which the outer edge of a road is elevated above the inner edge, and it is used to provide added stability and safety for vehicles traveling on a curve.

Purpose of Curves in Land Surveying

The purpose of curves in land surveying is to measure and map the curvature of roads, rivers, and other natural features on a piece of land. 

This information is used to determine the safe and efficient design of transportation infrastructure. Such as roads and railroad tracks, as well as to ensure proper drainage and to prevent erosion in the case of natural features like rivers.

So, the purpose of curves in land surveying is to ensure design of transportation infrastructure and natural features, by accurately measuring and mapping the curvature of roads, rivers, and other features on a piece of land.

Elements of Curves

There are several elements that are considered when surveying curves in land surveying. These include:

• Radius of the curve: This is the distance between the center of the curve and the point on the curve where the measurement is being taken. It is used to determine the safe and efficient design of transportation infrastructure, such as roads and railroad tracks.

• Central angle of the curve: This is the angle between the two tangents that touch the curve at the point where the measurement is being taken. It is used in conjunction with the radius of the curve to determine the safe and efficient design of transportation infrastructure.

• Grade or slope of the road or other feature: This is the vertical change in elevation over a horizontal distance and is used to ensure that the road is safe for vehicles and that water will drain properly.

• Superelevation: This is the amount by which the outer edge of a road is elevated above the inner edge and is used to provide added stability and safety for vehicles traveling on a curve.

• Stationing: This refers to the process of measuring and marking the location of points along a road or other feature. Stationing is used to establish a reference system for the survey, and the measurement of the curve is then referenced to this system.

• Profile: This is the representation of the vertical alignment of a road or other feature, showing the elevation at various points along the curve.

• Cross-section: This is a representation of the horizontal and vertical alignment of a road or other feature, showing the width, depth, and slope of the road at various points along the curve.

Advantages of Curves

There are several advantages to using curves in land surveying, including:

• Safety: Curves provide a safer and more efficient design for transportation infrastructure, such as roads and railroad tracks. They allow for vehicles to navigate turns at a slower and more controlled speed, reducing the risk of accidents.

• Drainage: Curves can also help to improve drainage by allowing water to flow off the road or other feature in a controlled manner, preventing erosion and reducing the risk of flooding.

• Aesthetics: Curves can also add visual interest to a road or other feature, making it more pleasing to the eye and contributing to the overall aesthetic appeal of the area.

• Reduced wear and tear: Curves also help to reduce wear and tear on vehicles and infrastructure. They allow vehicles to travel at a slower and more controlled speed, reducing the stress on the road and vehicles.

• Cost-effective: Curves are cost-effective compared to other alternatives like straight roads. They require less land and materials, which results in lower construction and maintenance costs.

• Better alignment with natural features: Curves can be designed to align with natural features of the land, such as rivers and valleys, making the road or other feature more in harmony with the surrounding environment.

• Accurate measurement: Curves surveying allows for accurate measurement of angles, distances, and elevations, which is crucial for construction, land-use planning, and other important applications.