3D Drone Mapping Made Easy with Pix4D & DJI Phantom 3
Using a drone to get imagery for 3D mapping is rapidly catching on, and thanks to Pix4D software, they’ve made strides in bringing the technology to the small UAV market. We’ve only just begun to see where this technology is going to take us, and how we can best utilize it for industry. New designs in drone hardware, cameras and software applications such as the DJI Phantom 3 Professional with the DJI Go app are really pushing the envelope.
3D Mapping is commonly used for different types of surveying needs such as mines & quarries, precision agriculture, geological studies and surveys, archaeology, construction/grading and much more. We’re really just scratching the surface as to how this can be used in the future, and the technology and ease of use will only get better.
Earlier this year, working with DJI on early application prototypes, Pix4D gave us a glimpse of the future with an app that ran with the Phantom 2 Vision+ to create a small area map that you could place over a Google map and specify the height and X-Y dimensions of the flight path. The Phantom would then automatically take off, shoot the mission and return to land by itself. You could then let it upload the files to the cloud and process everything automatically or download them and use the desktop software to process & render your finished map.
While this was exciting new technology and the capability to automate the process with a relatively inexpensive UAV, it had limited range and results – but still it created a pretty complex map if you could capture everything in it completely.
Again, this was a first generation prototype app and new versions & updates to both Pix4D and DJI apps will accommodate a much more sophisticated workflow in the months to come. With autonomous flight plans coming soon to the DJI Phantom, we can expect a lot of updates to this software’s capabilities as well. Currently, some are testing DroneDeploy’s software to program their flights and then bringing the recorded data into Pix4D with some good results, but it’s still not a perfect workflow just yet.
Several of us have been flying the DJI Phantom 3 Professional and manually capturing JPGs on a flight path to capture the data necessary to create a detailed map – quite successfully too. It’s just a matter of planning out your desired map area and sending the craft up to a desired height and flying a grid pattern at the fixed height while maintaining approximately a 70% overlap between shutter clicks. If you’re flying around a subject, such as a building, then you will want to circle around it shooting toward the center at a 45º angle and up to 90º if you have enough clearance to get all the way around the structure.
The DJI Pilot app (now called DJI Go) saves the flight in the cloud so you can bring it up later to retrace the path you made during your flight.
Here’s an example of a simple map I created of a barn out in Oshkosh when I was there for EAA Airventure 2015 (the flight plan shown in the above image). We drove around looking for the perfect barn and when we found one along the backroads, we stopped and asked the farmer if we could fly our drone and capture some photos of his barn for a 3D map. He was intrigued by the technology of the Phantom 3 Pro, being an old RC pilot himself and the flight took a total of about 18 minutes to manually capture 83 JPGs for the map. Since the Phantom 3 Pro saves not only the camera data but also the GPS telemetry data to each image file, Pix4D can easily geotag the location and build a high-res model from the series of images.
The Pix4D software takes a bit of a learning curve to understand what parameters you may need, but given the correct JPG files from the DJI Phantom 3 or Inspire 1, it will almost ingest and process the entire map automatically. Once Pix4D has calculated and processed the Orthomosaic Map, Point Clouds and Triangle Mesh, you will be able to use a preset animation to render or choose your own trajectories to create a custom animation path. You can chose to view the camera planes with rays and tie point, the point cloud or simply render the final 3D Orthomosaic Triangle Mesh (full version only).
For more information, including PDF and Video tutorials on Pix4D software, check out the Pix4D Academy page and download the free Pix4Dmapper Discovery software here. You will see the various rates for renting the full-featured software for month-to-month, annual or a one-time lifetime fee to purchase.
An important note* is the hardware necessary to fully render the Pix4D Orthomosaic Triangle Mesh in animation. Please refer to the following hardware requirements as listed on the Pix4D website:
Minimum requirements: Windows 64bit / 7, 8, Server / 2-Core CPU / 4GB RAM / GPU: any Nvidia and AMD model starting from 2008 and Intel model starting from 2012 (OpenGL 3.2)
Recommended: 6-Core CPU i7 or Xeon /16GB RAM (or more depending on dataset size) / CUDA compatible GPU
*Orthomosaic Triangle Mesh will not always render correctly running in Windows 7 on a Mac’c bootcamp partition or in VMware. It’s best to install and run on a dedicated PC instead. No word on when they may have a Mac version of the software at the time of this article.
Stay tuned for more updates coming soon…