“Imagine for a moment that you are a person who owns a falcon. You don’t own the falcon just to have an unusual and intimidating pet but because you are a licensed falconer, among the growing ranks of Americans dedicated to the ancient and complex art of training birds of prey to hunt in partnership with humans. As part of your falcon’s schooling process, you must teach her to fly high, high enough to scan for prey and gain enough altitude to speedily swoop down on a smaller animal—and this is a challenging task, especially if you are a human being who is stuck on the ground. An increasing number of falconers around the world are solving this ancient logistical problem with a decidedly modern tool: a drone.”
I decided to read “H is for Hawk” as I was writing this piece, which did indeed provide me with some interesting insight into how falconry works, but also was the most enjoyable reading experience I’ve had this year. On one level, it is a great exercise in writing about a esoteric or technical topic in a way that is not even a little dry. Helen MacDonald writes like an old kind of writer, I guess, which is inadequate but the only way I can put it. It was not surprising then that she had so much affection for E.B. White.
I’ve also had a long weird relationship with White’s writing, but also a kind of profound one. “The Once and Future King,” naturally – a book that actually can grow with you, one I’ll likely end up reading every five years or so until I’m dead. The book I read when I was 8 is not the same as the one I read at 17, and then it meant the most of all at 22. MacDonald captures with her simultaneous grief over her father and the agonizing and bizarre process of hawk-training what White means – this bizarre, eccentric man who so well conveyed emotional pain, uncertainty, fear.
I recently bought a Phantom 3 Professional, operating under the logic that it costs $1200 and is therefore much more economical than a hexacopter. Myself and my partner, Daniel, are working on developing expertise in 3D mapping with a UAV, and I’d been looking for a new model capable of waypoint navigation and shooting high-quality, undistorted still images. My Phantom 2 still worked great, but it wasn’t great for mapping – built to use a fish-eye lens GoPro camera, and unable to carry out waypoint navigation without extra, expensive parts.
I was really sold on buying a Phantom 3 Pro after I visited the DroneDeploy offices in San Francisco and watched a demo of their waypoint navigation software, which is paired with their cloud computing processing. You fire up your mobile phone or tablet, sync it with the Phantom 3, then draw a box around the area you want to map. The software calculates how many times the Phantom will need to cross the area, the altitude of the area, and how many pictures are required, then you press a button. The Phantom proceeds to launch itself and carry out its work without your input, though you can always call it back from the controller. Simplicity. I like it.
So, I bought a Phantom 3 Pro— and since I live in the giant no-fly-zone otherwise known as Washington DC, I had it shipped to Daniel in Boston where I regularly visit him. On my last visit in early September, we decided to test out DroneDeploy and the Phantom 3 by using it to map the abandoned Medfield State Hospital in Medfield, Massachusetts, which I’d found out about on Atlas Obscura. (Scenes from “Shutter Island” were filmed there). Unlike most creepy, abandoned mental hospitals, this one had been opened to the community for use as a park, while the town decides how best to redevelop it. It’s a sprawling complex with red brick architecture and lush greenery around it in summer, with the Charles River bending towards one corner.
We parked across the street and walked in, and identified a parking lot where we could easily launch the drone from a flat location. DroneDeploy synced up easily enough with my Phantom 3, and I chose to map about half of the area, going conservative for a fist-time experiment. I pressed the button. It worked great: the Phantom efficiently flew off in the designated pattern, in neater lines then I could manage myself. It retuned to home in about 15 minutes, and landed itself, albeit with more force then I’d like. I may, in the future, switch back on manual control of the Phantom as it comes in to land after a DroneDeploy mission, as I prefer to catch it rather than landing it.
Since DroneDeploy missions currently can’t be flown with the camera at an oblique angle, I manually shot my own oblique imagery, with the Phantom 3 camera set to shoot images every five seconds. I flew reverse transects from the DroneDeploy pattern, and – following advice from DJI’s Eric Cheng – flew the drone in large, slow circles over the area I want to map. I probably should have worked with alternating the altitude more, but I was pleased enough with the images I was able to collect. The Phantom 3 handles even more smoothly than the Phantom 2, and shoots beautifully crisp still images with its 12-megapixel camera, without the distortion that used to annoy me with the GoPro.
We used both DroneDeploy’s processing tool and Agisoft Photoscan 3D to process the final imagery. Daniel has a great summary of the pros and cons of each over at his blog, so I won’t recap them – but in summary, DroneDeploy was a lot faster, while Agisoft PhotoScan had higher quality results but took a longer time and required much more processing power, and also required us to manually fill in some holes in the mesh.
Here is the final, orthorectified map. DroneDeploy’s ability to quickly orthorectify 2D maps using cloud processing is definitely handy. In the 3D model, DroneDeploy was not able to incorporate our oblique imagery successfully, although we’ve been in touch about the problem, and they’ve told us it will be fixed. There’s two other problems with DroneDeploy as of this writing: it only works with Android phones and tablets, and it requires either Wifi access or mobile data to function.
Both features are in the works, but keep this in mind if you want to experiment with it.In Agisoft Photoscan, which did use our oblique imagery, the sides of the model weren’t as detailed as we’d like – though, some of this is to be expected when mapping an entire complex of buildings. We could probably fix this by taking the time to shoot oblique imagery around each individual building, but this would take quite a bit of extra time and battery power. (I’d like to try it anyway).
Overall, I’m very pleased with the Phantom 3 Professional as an inexpensive mapping tool, and I’m excited to see what we can come up with next. I’m also interested in doing more work with DroneDeploy – and I eagerly await the release of the off-line version, which should make it a much more viable tool for field work. What else could we map in the area around Boston?
We’ve finally done it: the “Drones and Aerial Observation” primer I’ve been working on for New America with support from the Omidyar Network and Humanity United has been released into the wild. Ever wondered how drones can help with peaceful endeavors, from disaster response, to conservation, to archaeology? We have you covered.
With this book, I’m of the mind that myself, my colleague Konstantin Kakaes, and the drone experts who contributed chapters have created an overview of drone technology accessible to people who don’t already know what a “gimbal” is. (Yes, I am aware that is a funny word).
We hope the book will encourage people to start thinking of drones as a tech they can practically use for their own field endeavors. While drones certainly look complicated when you first encounter them – at least, that’s how I felt about them – it’s a tech that’s remarkably accessible to people who don’t have aeronautical engineering PHDs.
On my end, I wrote chapters 4 and 5: “How to Make Maps with Drones” and “Mapping in Practice.” Writing these chapters was a real crash-course in drone mapping for me, and I’m grateful to come out the other side alive and with a better sense of what’s required to carry out mapping projects. I hope I can pass that on to you. I’m also planning to get my own mapping drone in the very near future so I can start carrying out some of this work myself.
I also wrote Chapter 9, which is a case study of the world’s largest archaeological drone mapping project, carried out by the Ministry of Culture in Peru. They were incredibly hospitable to me, and I had a great time watching the researchers deal with the quotidian, difficult, occasionally terrifying realities of making maps with drones in remote and difficult areas. Many thanks to Aldo Watanave and Dr. Luis Jaime Castillo Butters for taking me along for the ride. A Slate piece about this work is impending as well.
If you know me at all, you’re probably aware that I write about and research the humanitarian uses of drones for a living. One aspect of today’s drone technology I find particularly interesting is how aerial imagery can be used to make 3D modeling, even with inexpensive consumer technology. I’ve been wanting to try it for a long time.
Well, I don’t currently have a UAV that I can program for autonomous flight, to create the pattern of transects that allow drone-shot images to overlap in an optimal way, so they can be stitched together to create maps and 3D models. I also don’t have a point and shoot camera, just a GoPro Hero 3+ with a fish-eye lens, which is rather less than optimal for mapping applications.
But as it turns out, with the help of the open source Visual SFM software, you can *still* get pretty good results. I was visiting my boyfriend Dan’s family in Southwestern Vermont last weekend, which is a really ideal place to mess around with drone mapping since there are very few people there to notice. My friend Matthew Schroyer of the Professional Society of Drone Journalists has been getting good 3D modeling results just by pulling out video imagery from drone videos shot by amateur pilots.
So, I figured I’d give it a go and see what we got. I flew my Phantom 2 over my boyfriend’s parent’s house in some approximation of a zig-zag pattern, with the GoPro 3 set to shoot an image every second – probably overkill, all things considered. I eyeballed the pattern, and since it was a bit of a windy day, it wasn’t as tight as I’d have liked it to have been.
With the initial fly-over done, we had a few hundred images that could be fed into Visual SFM, which Dan handled. Dan says the VisualSFM model used 378 photographs and took about 20 hours to render using his late-2013 Macbook Pro Retina laptop. That’s including the time required to render the image in MeshLab, which creates the mesh required for three-dimensional modeling and overlays the photographic texture on top of it. You can read about how you can use Visual SFM to crunch images over at the excellent Flight Riot.
Agisoft Photoscan performs all these functions inside of the same program, and is a more effective and powerful software, although unlike Visual SFM, it isn’t free. Dan ran the images through Agisoft Photoscan and added some still shots from a video we’d taken the day before, but it didn’t seem to make much of an improvement to capturing the backside of the house, which was quite fragmented. He ran it again with 75 photos, taking out the video stills, and got a better result with fewer artifacts.
The results obviously aren’t perfect, but considering how little effort or specialized equipment we used, I’m still impressed. I’m planning to have a good quality mapping UAV with a point and shoot camera and the ability to program transects up and running by July. I think that there’s some very interesting potential for story-telling and journalism with 3D modeling, and I want to figure out ways to experiment. Beyond that, it’s rather fantastic that I can use consumer-grade technology to made video-game like maps of the world around me.
Phnom Penh’s Olympic stadium is saddled with a bit of a misnomer. Begun in 1963, the earthworks-heavy structure was crafted by revered Khmer architect Vann Molyvann, and was originally intended to host the 1963 Southeast Asian Peninsular Games. Politics got in the way, but the stadium and its 50,000 person capacity persist to this day.
Probably the most colorful incident in its history took place in 1965, when the now deceased King Norodom Sihanouk offered up the place for the FIFA World Cup.
The reason? North Korea, to the shock of everyone, faced Australia in a qualifier, and few countries were diplomatically suitable to receive the DPRK delegation. Sihanouk, a long time friend of North Korea, proved to be a handy go-between. Olympic Stadium hosted the matches in November of 1965, and in incidents that should prove rather awkward for Australian national pride, the DPRK won them both.
Some of its history is rather more dark. Prior to the Khmer Rouge invasion and during the troubled Lon Nol period, it served as a refugee camp and field hospital (per the records I’ve dug up), providing some measure of shelter to the thousands upon thousands of refugees who streamed into Phnom Penh from the countryside during this period. Upon the Khmer Rouge take-over of the city on April 17th of 1975, numerous military officers were taken to the stadium to be publicly executed.
Nowadays, the stadium is a pleasant spot in the center of the city that is particular favored by local Cambodians in curious spandex get-ups, footballers of various nationalities, and kids playing pick-up games. I admit I’d never been there before I got my Phantom 2, driving by it constantly but never managing to carve out the time or motivation to hop off the bike and have a look. Now, I’ve got a certain new-found appreciation for one of Phnom Penh’s architectural landmarks.
I shot (most) of these images during Pchum Ben, when the city was pleasingly quiet and empty as a result of the extended religious holiday. If you’re keen to do the same with your own UAV, it’s responsible to shoot at a time when the stadium is relatively empty. The security guards seemed profoundly disinterested in what I was up to, but I’d keep an eye out. It was also surprisingly windy around the stadium in late September, but once I was above 20 feet or so, it slackened a bit and the UAV proved easy to control.