credit: process.st
Overview
So you want to be on top of your game when it comes to drone mapping?
We have often found all important steps and advice around drone mapping to be scattered and hard to put together in one place.
This is why we have created the ultimate checklist for drone mapping. Let's go!
The Checklist
1: Follow the geometry of the structure you want to map or 3D model
Following the geometry of your structure helps reduce anomalies in your final processing and helps to concentrate on the subject that you are collecting data for.
For more info see our post: Improving the quality of your drone maps and 3D models
2: Capture Both Nadir and Oblique Shots
Using this method you can ensure that your structure or subject is captured from all angles so your final 3D model will have no missing areas.
For more info see our post: Improving the quality of your drone maps and 3D models
3: Ensure High Overlap Between Images
High overlap should be between all shots, not just the nadir. Ensure that both your nadir and oblique shots have at least a 70% overlap when you are collecting data.
For more info see our post: Improving the quality of your drone maps and 3D models
4: Use Good Exposure Settings
Having the correct exposure set greatly improves the quality of your data collection and your final 3D model or map.
For more info see our post: Why Automatic Exposure is a bad idea.
5: Choose a Camera with a Large Sensor Size & Megapixels
Choose a camera with a larger sensor and Megapixel rating, the higher the sensor size the more information will be captured.
For more info see our post: Camera Specs and Megapixels - Do they matter for drone photogrammetry
6: Ensure your subject is well-lit.
Shadows, reflections and transparent objects can affect the way the software process the final images.
For more info see our post: A guide to drone photogrammetry
7: Avoid Moving Objects
Avoid moving objects in the mapping area or in the background as these will cause artefacts in the final render.
For more info see our post: A guide to drone photogrammetry
8: Keep the Subject on Target
The structure, building, or area you are mapping should always fill the main part of the image to ensure data collection is accurate and you are only collecting the subject that is required.
For more info see our post: A guide to drone photogrammetry
9: Capture The Entire Site or Structure
Ensure that all of the site or structure can be seen in the neatly overlapped photos.
For more info see our post: A guide to drone photogrammetry
10: Avoid Motion Blur
Motion blur is caused when the drone’s flying too fast with respect to the shutter speed causing the scene to substantially change over a single camera exposure. Adjusting the camera settings will help to eliminate this.
For more info see our post: Preventing Motion Blur in Drone Photogrammetry Flights
11: Use GCPs, RTK or PPK (if accuracy needed)
GCPs, also known as Ground Control Points are points that are laid out on the ground that have known coordinates. These points are laid down across the site and are measured using an accurate GPS device for example the DJI D-RTK 2 GNSS Mobile Station to gain centimetre accuracy. This data can then be tied in with the GPS information to create your final photogrammetry image.
For more info see our post: GCPs vs RTK vs PPK what is best?
RTK stands for Real-Time Kinematic and is a technique used to increase the accuracy of GNSS (global navigation satellite system) positions using a fixed base station that remotely sends out data to a moving receiver.
For more info see our post: GCPs vs RTK vs PPK what is best?
PPK stands for Post Processed Kinematic and is a method of correcting the data after the flight has taken place and the data has been uploaded.
For more info see our post: GCPs vs RTK vs PPK what is best?
12: Use the Same Focal Length
Used a fixed focal length lens, do not change the focal length or zoom whilst shooting as this will cause discrepancies in the collection of data.
13: Use Optimal Flight Speed
A carefully calculated flight speed will help your drone fly fast enough to be efficient and also slow enough so that the data collected is of high quality.
For more info see our post: How to Calculate the Optimal Flight Speed in Drone Missions?
14: Use Ground Offset
Ground Offset is the height of the structure you’d like to survey assuming you took off from the ground and not from the roof of the structure.
For more info see our post: Ground Offset in Hammer Missions
15: Verify your Data
Data verification involves checking and verifying the data before leaving the job site.
For more info see our post: The missing step in Drone workflows
16: Use High GSD for Accuracy
Ground Sampling Distance, as the name implies, refers to the amount of ground/surface area covered by a single image in flight. The higher the GSD the higher the quality of data collected.
For more info please see our post: Accuracy of stockpile volumes
17: Use a Global Mechanical Shutter
Global shutters ensure that each image on the image sensor is exposed to light at exactly the same time. Global shutters are inherently good at capturing subjects in the scene which are flying fast since all pixels on the camera are exposed to light exactly at the same time.
For more info see our post: Global Shutter vs Rolling Shutter: What’s the difference and Why does it matter?
18: Use The Correct Flight Altitude
There are several factors to consider when thinking about using the correct flight altitude, GSD, and regulations, but above all safety.
For more info see our post: How to Decide Flight Altitude for Drone Mapping and Inspection?
19: Use Terrain Follow When Needed
This is a feature that allows the collection of more accurate data for mapping, 3D mapping and magnetic survey missions' challenging terrain by adjusting the mission's altitude to maintain a constant GSD.
For more info see our post: Terrain Follow in Hammer Missions
20: Use Fly-to-Draw for vertical structures
Fly to draw is a feature where you use the drone to mark points on your asset for your missions. Ideal for facades, towers and wind turbines.
For more info see our post: Precise Asset Inspections using Fly-To-Draw in Hammer Missions
21: Avoid manually Edits to the data
Do not crop or post-process the images in any way that would affect resolution or focal length!
22: Be Aware of Distances
Don’t be extremely close to the object/site of interest and don’t be too far! The distance needs to be just right, find a happy medium and find the right GSD!
For more info see our post: Calculating Ground Sampling Distance (GSD) in Drone Flights
Summary
We hope this checklist helps you get the most out of your planned mapping missions.
Think we missed something? Let us know in the comments below and we'll add it to the post!
If you'd like to learn more about how to produce 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 of 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 team@hammermissions.com
We look forward to hearing from you. - Team at Hammer Missions