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Public Lab Research note


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Mapping Rural Alberta's Wetlands

by Rural |

Background

Alberta, Canada, has a great deal of land area in wetlands and has fairly strong laws in place to protect those wetlands. Despite those protections, wetlands are illegally drained and filled-in each year, mostly for conversion into farmland, but also for development projects of all kinds. Alberta's provincial government has a department in place to handle permitting of wetland modification and to levy fines against unpermitted modification. Satellite imagery is readily available, and despite its age (several years) can serve as a historical record of the land's state. A ground-based photo can make it obvious that a particular wetland area has been modified, but aerial photography provides much better evidence. Drone-base, kite-based, or balloon-based photography can be used to quickly generate aerial imagery that reflects the current state of a wetland (or former wetland).

Goal

I would like to come up with a quick method to map wetlands. Once a wetland is mapped, it is protected from illegal modification, in the sense that a modification can easily be shown to the authorities. By examining historical satellite imagery, a motivated citizen could set out to map areas that may have been modified and use the resulting imagery as evidence for the authorities. To be clear, I'm not sure that this is something I want to do personally, but I have no problems helping to seed some local knowledge that could enable this sort of action.

Although I can see a fixed-wing drone as an efficient tool for mapping large areas, my dog ate the expanded polystyrene RC plane that was serving as my drone test-bed. Besides, I would like to promote a tool that is accessible to as many as possible. Drones demand a technical aptitude that isn't common and are expensive compared to a kite-based mapping kit. Worse, RC plane- or quadcopter-based drones suffer from a stigma that could complicate conversations with curious observers or concerned land-owners. A kite-based tool is far less concerning to most.

My attempt and results

I have obtained a Public Lab's Kite Mapping Pack, which contains a 7-foot Hi Sky Delta, a 9-foot Dazzle Delta, and a 15' fuzzy tail. 1000-feet of 150-pound Dacron line was ordered separately and recently arrived, although most of my testing to date was using 400' of 125-pound test nylon cord (from our local farm store).

Both kites have been out for about ten test flights in a variety of conditions without a rig. In low wind conditions I have been consistently surprised at how acceptable air is found above 100'.

My experience with the kites has been positive over-all. The 15-foot fuzzy tail is always attached to the centre loop if there is enough wind to allow it. I wouldn't attach a camera rig to either kite without the fuzzy tail in place at this point. The Dazzle seems to move around much less to the Hi Sky in similar winds. The Dazzle also flies at a much higher angle than the Hi Sky in similar winds. Just a bit too high, in my opinion.

I do feel it is worth mentioning that the Dazzle Delta has a habit of pointing its nose at the ground and staying so until it the Earth stops it. This occurs in stronger winds with or without a tail. Letting out line is a possible fix, although I have not been able to test this yet.

Given appropriate wind conditions for the Dazzle, it is by far the better KAP platform as it flies higher and with much less motion.

A line reel has been constructed from some plywood and skateboard wheels. It works acceptably, but is over-built and not properly balanced. Reeling in a kite when there is decent wind is still tiring. Letting line out can get exciting too.

My camera rig is based on the Kaptery's Redstone Rig. I have used locally available replacements for fasteners and the fibreglass rod.

For now, my KAP camera is a Canon SD1100 IS with CHDK firmware installed. After three kite-mapping sessions, I find the quality to be acceptable. The motion of the camera as it hangs from the kite usually limits the quality of photographs to below the capability of the camera. Out of about 500 images, only a couple of dozen have been as sharp as the SD1100 allows. At this point, a better camera probably isn't justified.

Next steps

Another 1000 feet of kite line would be useful as it will allow high-altitude images that cover a large area of land. These images are very useful in MapKnitter, greatly easing the warping of lower-altitude higher detail images.

Figuring out how to lock my camera's settings to a particular exposure is necessary. Currently, the camera's automatic exposure creates images that are wildly different. A software tool to post-process the images to better match would also be useful.

A tool-chain to remove blurry images, correct lens distortion, crop away the outer third of images (reducing perspective issues), and bring a set of images exposures into alignment, is a necessary prerequisite to making really decent MapKnitter maps.

More experience with kites is definitely required. A kite-enthusiast meet-up would be hugely useful.

A stabilized rig might greatly increase the number of useful images that can be obtained in a given amount of flight time. If so, it would allow a better camera to be used.

A Levitation Delta from Into The Wind may be in my future.



kite-mapping wetlands blog alberta


13 Comments

Ah, those were the days when the boy might have considered joining me for KAP. Enjoy it while you can.

SunOrchMid-20120429-132-21.jpg

It sounds like you did some useful experiments with fuzzy tails. Maybe a little keychain camera right on the kite recording video would be a good way to compare kite stability.

An SD1100 was also my first kite camera. Great choice.

I think the best lesson is that it doesn't take much wind to fly a kite. You avoided the common mistake of waiting for a windy day to try kite photography.

Can't wait to see your rig flying.

Chris


Chris, agreed on the best lesson being how little wind it takes to fly a kite. Yesterday, I was able to sneak in a 45 minute kite session where I learned the opposite lesson. On the same hilltop, the wind was blowing fairly hard, much more than a breeze. So I took out the 7-foot Hi Sky Delta. As soon as it was in the air, I knew that I would never hang a camera off of it in similar conditions. It darted to either direction fairly violently. I let out all of my line, thinking that cleaner air would make a difference, and it did, to a degree. Brought it back in and attached the fuzzy tail before launching again. That helped a bit too, but not enough that I would risk a camera rig. It took a long time to reel in all the line (haven't finished the new reel yet).

When I looked up the wind speed for our area for the time that I was out, it was between 24-39 km/h (15-24 mph). Now I know.


Another excellent lesson. But part of that lesson is that 25 mph winds are a problem that can be solved with money. A big soft kite like the Parafoil 10 (http://www.brooxes.com/newsite/BBKK/kitesales.html) or a sturdy delta like the nighthawk (https://publiclab.org/notes/cfastie/10-12-2015/pfk-nighthawk-debut-at-leaffest) can handle 25 mph winds if they are steady enough. You might also need 200-300 lb line and good gloves.


I'm excited to hear you're experimenting with the tails in the kite pack to place your camera where you want it. I've had a good bit of success flying off wind by using asymmetrical tails:

flying off wind

here are my notes summarizing my methods and those of others, primarily people who use fishing kites like the Nighthawk delta that @cfastie suggested:

https://publiclab.org/notes/mathew/2-1-2013/how-pauls-fishing-kites-flys-wind https://publiclab.org/notes/mathew/2-1-2013/american-kite-fishing-low-tech-kite-balloon-hybrid https://publiclab.org/notes/mathew/2-14-2013/flying-wind-dazzle-delta


Chris, I've been researching soft kites since my experience yesterday. Perhaps as a reward to myself when I've mastered the basics...

Mathew, I'd read your research notes on flying off-wind with the Dazzle Delta, but those kite-fishing videos were new to me. Very interesting. Thanks a bunch.


Awesome post @Rural! If it's alright with you I'd like to tag it to the blog!


Sure @stevie. With the expectation (and fear) that more people would see my post, I gave it another read and spotted some errors and missing bits of information. I'm not seeing any way to edit the original post. Am I just over-looking something obvious?

Is this a question? Click here to post it to the Questions page.


You are overlooking something hidden. The edit button is in the "Follow" "Like" bar at upper right.

Chris


Ah! Found it. Thanks. The gear is a red-herring if you are looking to edit.


So I received 1000' of 150-pound Dacron this morning. Early this evening, I dragged my sons out to a nearby football field to try giving a kite 1000' of line. There was enough wind that the Hi Sky Delta was our choice. That went well and uneventfully.

When we got home, I realized that my Redstone-based camera rig only needed about half-an-hour of work to be useable. I finished with was enough time before dark to take it out for a test. So I was back at the park with a hastily filled backpack with some extra bits-and-bobs so that I could anchor the kite and attach the picavet. Not all of the right bits-and-bobs, as it would turn out, but enough that I was able to get the Dazzle Delta and the rig into the sky. With about 500 feet of line out, and only three minutes into the air, things became interesting.

At that point, the Dazzle Delta decided to point its nose back at the Earth. Down it went, with the camera rig on the line. Before it hit the ground, I decided to run backwards to try to keep everything on the football field, but it was out further than I thought. It went down in a nearby trailer park. I could see that the line was draped over power lines, trees, and a row of trailers.

Hastily, I rolled up what line I could, packed up my stuff and left the roll of line in the football field. I followed the line without having to trespass, found the rig was intact and sitting on someone's porch, and the kite was in a small tree right at the far edge of the trailer park. Another twenty feet and it would have been on a well trafficked roadway.

I knocked on a door and eventually got someone to answer. With fear of trespassing charges removed I was able to get to the kite. Detaching the kite from the line was quick and easy since I have recently adopted the Lark's Head knot. Packed up the kite and headed to the camera.

In my haste to launch, I had left the camera in "automatic" mode. So every ten seconds, it would take a picture with the flash. The camera was sitting on the property owner's front patio and the flashing had attracted their attention. They had just stepped outside, in their house-coats, when I walked up. I apologized profusely and they were ultimately relieved when the situation was explained.

I hopped a fence and went back to reel up my line. It only caught once, and was freed with a single tug.

So no equipment lost, property damaged, or charges laid (as of yet). I think I may have even made a friend.

IMG_2429.JPG

Figure 1. This image was taken as the kite began to rapidly descend. The camera is headed for the patio at the top right.

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Figure 2. Ten seconds later the camera is a whole lot closer to the ground and moving fast.

IMG_2431.JPG

Figure 3. Another ten seconds and the camera has stopped, hanging about six feet off the ground. I found it sitting right next to the garbage can. Very exciting, but no contribution to science was made.


Whew! All's well that ends well!

@Rural Every once in a while a freak gust or wind shift will send a kite headed downwards (or high wind conditions outside the kite's flight range) there's a quick but counter-intuitive fix-- let line out until the kite rights itself, then give it a tug to lock in a clime.

Letting line out is the secret to correcting dives. remember "when in doubt, let line out!"


In the five or so seconds I had to react, I ruminated on giving the kite line or taking it in. Unfortunately, I went with the intuitive solution. On the walk home, I was pretty sure that letting the line out, or running with the wind, would have been a better solution. Its good to get some confirmation for the next time this happens.

Certainly, I was flying at the upper edge of the Dazzle Delta's range. Chalking this up to experience.


We need a lot more stories like this of KAP sessions gone awry; there is a lot more to learn here than when everything goes well. But maybe most of these stories are never shared (or have some details left out) to protect the innocent. Now that I review my 2011 post about losing my new Fled kite to a tree, I see that I neglected to mention that I pulled very hard on the line as the kite dove into the forest. I had no knowledge that the first lesson of kiting should be that pulling the line just encourages errant kites. The Fled should have had a tag which said "Let line out fast to stop a dive" (and also "Do not remove under penalty of crashing").

I am glad Rural's gear survived to provide more stories.


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