Step by step guide to Topographical Drone Surveys

Topographical surveys are vital for industries like construction and mining. Traditionally, these surveys were time-intensive, requiring ground crews, specialised equipment, and days, if not weeks, to complete.

Enter drones: a game-changing tool that makes topographical and mapping surveys faster, safer, and more accurate.

This article explores how drones are used to create precise digital maps and 3D models, breaking down the process into simple, actionable steps. Whether you're new to drone surveying or looking to refine your technique.

Why use drones for topographical surveys?

• Enhanced accuracy: Modern drones equipped with advanced sensors like LiDAR or RGB cameras collect high-resolution data, resulting in pinpoint-accurate maps.
• Time efficiency: What used to take weeks can now be done in hours, allowing for faster project completion.
• Cost savings: Reduced reliance on ground-based crews and equipment translates into significant savings.
• Improved safety: Surveying challenging or dangerous terrain can now be done remotely, minimising risk to personnel.

Step-by-step guide

Step 1: Planning the survey

1. Define objectives: Understand what data you need, contours, elevation models, or a detailed 3D map.
2. Select the right drone and payload: Choose a drone equipped with the necessary camera or LiDAR sensor. For instance:
1. DJI Matrice 350 RTK paired with the Zenmuse P1 for photogrammetry.
2. DJI Matrice 350 RTK with the Zenmuse L2 for LiDAR mapping.
3. Map the area: Use a flight planning app (e.g., DJI Pilot 2 or Pix4D) to set the survey boundaries and determine flight paths.

Step 2: Executing the flight

1. Calibrate equipment: Ensure the drone and payload are calibrated to collect accurate data.
2. Fly the mission: Execute the pre-programmed flight plan. Maintain line-of-sight (or BVLOS with the necessary approvals) and monitor flight progress.
3. Capture overlapping images: Ensure overlap between the images, and good starting point is at least 75% front and 60% side overlap in images to aid post-processing.

Step 3: Data processing

1. Import data: Transfer collected images and sensor data into mapping software.
2. Process the map: Use software to generate outputs such as orthomosaics, contour maps, or 3D models. Popular software includes:
1. Pix4Dmapper: Excellent for detailed photogrammetry projects.
2. DJI Terra: Optimised for DJI drones, it provides seamless processing for photogrammetry and LiDAR data.

Step 4: Validating results

1. Ground control points (GCPs): Compare drone data against GCPs to verify accuracy.
2. Adjust outputs: Make corrections or refine data as needed using software tools.

Step 5: Deliverables

1. Create final outputs: Generate deliverables like Digital Elevation Models (DEMs), Digital Terrain Models (DTMs), or 3D surface models.
2. Share with stakeholders: Export data in formats compatible with GIS and CAD software for further analysis.

Drones are revolutionising topographical surveys, enabling businesses to gather precise data faster, safer, and at a lower cost. By following this step-by-step guide and using the right tools and software, you can unlock the full potential of drone technology for your mapping projects.

Ready to elevate your mapping with drone surveys? Get in touch with our team today or call us on 1800 119 111 to find out how we can help.