Go fly a kite!

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This afternoon for work, a kite was flown. Now, this was not just any kite. This kite had a name that involved "16", as that presumably is roughly the square footage of this beast. Being a gusty afternoon (Rachel clocked the wind speeds at anywhere from 7 to 27 mph). Having trouble getting the kite up by just letting the gusts grab it, I went to the house to grab a few more pairs of gloves (didn't want rope burn). As I returned, Rachel and Julie figured out the trick to get the kite up: run with it.


In fact, two people run with it. One holds the kite, the other the spool. They both run into the wind. At the right time (during a gust, most likely) the kite-holder lets go and the spool-holder keeps going. This will launch the kite high into the air. It's interesting to note that the kite pulls back. Hard. We didn't hook up the camera apparatus, though; our kite-flying skills are not yet honed (we're not well-oiled enough, probably) and we didn't want to break an expensive camera. The kite came down hard, incidentally.

Taking the kite down is a three-person job, ideally. One person spools the string (vertically! horizontally it twists, shortening the life of said string) while another pulls the kite down by the string. The third person is between them, feeding the slack to the spooler and preventing the kite from slipping back up while the puller is, ah, pulling. We had gardening gloves on to prevent rope burn. Effective in preventing rope-burn, ineffective in actually holding onto the damn string. We could really use gloves with rubber grips.

The final step is the actual photography part. Once we're good at flying the kite (Stuart says some call it "poor-man's sailing), we'll send up the victim camera to take our aerial photos. We tested the camera at various distances from the side of the storage building (looking for an echinacea-sized X of tape). At 40m (lower than our flying height, I fear), the tape was indistinguishable from the building. It may have been the settings, it may have been the shaded lighting, and it may have been the camera's tiny screen. We can't say until they're on a computer (not easy, as the card reader seems to have failed). While I'm not worried that the camera's 7.1MP resolution will be too small to discern detail, my concern is that the optics on the camera are simply not good enough to resolve something the size of flower-heads. The camera is a semi-compact camera; ideally, we'd have a good dSLR (Canon Digital Rebel XT[i] or Nikon d40[x]) with a high-quality and fast lens. This is expensive, though, and quite a bit heavier.

Anyway, since the images need to be meshed into a giant map-type image (we're like Google Earth, only without the satellites), there needs to be a way to have consistent landmarks in the fields we plan on photographing. This is where the painted wooden sticks come in. We'd (preferably) put flat, white-painted pieces of wood on stakes and place them in the field as markers to line up the images later. The final plans for this have yet to be made.

For now, though, we need to consistently get the kite into the air and onto the ground safely before taking pictures. We'll see how this goes.

2 Comments

Josh, Thanks for the low-down on the kite flying. We need to determine if the camera will do what we need. If not, we should get another camera soon!

Team KAP: figure out a method to determine if our current camera provides sufficient resolution to distinguish flowerheads from background prairie. If we need a DSLR, we will need to pick a lens. To make a good purchase, we will want to know how much area the camera will capture for a given focal length (zoom setting) and camera height. With a camera's pixel count you could then calculate the area covered by each pixel.

Here's a rough calculation: Suppose our resolution goal is in the 1 pixel per cm^2 (order of magnitude). A 10 megapixel camera produces images about 3000 pixels x 3000 pixels. So, we would want the camera to capture an image of about 30m x 30m of prairie.

What height would you want to fly the current camera when it's set to its shortest focal length?

What height would you want to fly the current camera when it's set to its longest focal length?

Great information - what type of kite was it? and was it auto adjust for the zooming? I have tried this without luck yet.

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