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  • Writer's pictureHammer Missions

What are Flight Lines and Tie Lines in Magnetic Drone Surveys

Updated: Sep 19, 2022

magnetic drone survey

Picture courtesy of SkyFront


In this article, we will discuss flight lines and tie lines and how they are relevant in drone magnetic missions.

Drones and airborne magnetometers have changed the game. Now a traditional magnetic survey can be conducted 5x faster and 10x cheaper using a magnetometer-mounted drone. Not only is the survey faster and more affordable, but it also results in higher resolution data collection as the drone (UAV) can be flown much closer to the surface as compared to a helicopter.

Hammer Missions helps you plan these missions with our range of modules designed for magnetic surveys.

When planning these missions you can adjust both the flight lines and tie lines to suit the needs of the mission but what are flight lines and tie lines and why are they relevant?

What are Flight Lines and Tie Lines?

Airborne magnetic data is acquired as a series of parallel survey lines, also more commonly known as flight lines, and more widely spaced orthogonal control lines also known as tie lines.

The purpose of the tie lines is to create repeat measurements at the locations where they cross the flight lines, which are required during the processing of the captured data.

You can clearly see the tie lines crossing the flight lines in the Hammer Missions Magnetic Mapping Mission example below:

tie lines and flight lines drone magnetic mapping

So let's take an example when collecting data for minerals and why tie lines are very relevant in the collection of that data.

We understand that the flight lines are required for the drone to follow as laid out in the mapping mission, tie lines help in the levelling of magnetic airborne data.

The magnetic signature of minerals have temporal variations, so collecting data using tie lines helps in levelling of the airborne magnetic data, and thereby removes the effects of temporal variations in the earth's magnetic field.

Tighter tie line spacing greatly improves the effectiveness of the levelling, to ensure that all of the data within the boundary of a survey area are properly levelled, all flight lines must start and end at a tie line.

These flight lines and tie lines can easily be adjusted in your planned Magnetic Mission in Hammer Hub

More information on planning and executing your Magnetic Missions can be found in our post:

Further reading regarding key considerations for magnetic surveying can be found here:


We hope this guide helps you understand more about flight lines and tie lines in magnetic drone surveys. If you'd like to learn more about how to capture high-quality data and get the most out of your drone missions, please feel free to visit our learning resources.

If you haven't got a Hammer account as yet and would like to try Hammer Missions you can get started on our free trial.

To learn more about our enterprise solutions, including mission collaboration, data processing, and AI solutions, please contact us at

We look forward to hearing from you.

— The Hammer Team


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