Why KAP is different to SUA photography

Positioning a camera by kite is a straight forward affair. You can either get over your subject or you can’t. The camera lies on the path between you and the kite and although catenary or slack line comes into play a little practice gets the 3D spatial awareness in place. One of the joys of KAP is the simple pleasure of working with the wind and discovering what it will let you do. It’s not entirely pot luck but with a line in the sky things are predictable, stable and self limiting.

Using a drone involves a very different kind of spatial awareness, things are fluid in a way the kite lofted camera is not. In practice for PfCO (Permission for Commercial Operation by the CAA) I have found the positioning of the camera in the sky by drone far more difficult than I had imagined. PfCO requires operation by VLOS (Visual Line of Sight) and FPV (first person video) is forbidden as a means of flight control. These 2 constraints kill the ‘flying view finder’ approach in favour of the far more demanding (but ultimately rewarding)  ‘manual’ control. I’m lucky as my SUA will not operate under ATTI mode (‘attitude’ mode where the aircraft is denied GPS stabilisation) and my flight test will be conducted in GPS mode with aditional manouvres to prove full manual control.

MVP2_Earith_Ortho_crop_02

Using a mix of manual positioning and the automatic ‘quick shot’ tools means rapid cover of fairly large areas: the orthophoto above is generated from around 90 frames captured using several ‘point of interest’ paths with a shot to shot interval of 10s in around 20 minutes at 400′ AGL.  The benefit here is the removal of the conflict with the 3phase power line (visible running along the left edge of the image) and the zero wind operation.

The coverage achieved by KAP (2nd, 3rd &4th from left) and drone (left) in this case are equal. KAP has the edge on resoloution as a bigger camera was flown lower.

Swavesey_03-4

KAP delivers but only when the wind permits. The ortho above was captured by kite to record the parch marks revealing the monastic site. A repeat flight to extend the mapped area never happened as the wind window remaind shut untill rainfall erased the marks.

The shot above is the one that drove me to the drone. I had been flown in to do the survey of the house, waited anxiously for a break in the weather, took a chance and failed to get the nadir cover I needed, to add to the frustration the wind cut and dumped my kite in a tree, I got the camera on the ground safely but only managed to free the snared kite by serious yanking on the line which invoved some hideous leverage and bough bending before the tail parted from the kite and released it.Ughh. The viewpoint captured is the view the kite let me have, given more time and a better wind I’d have got what was needed but most projects don’t have that much stretch these days.

The comfortable certainty of where I am in the sky is missing from the drone experience so far. As my flight skills build I can see how I could get to a point where I’m less anxious about placing the camera but keeping the orientation of the aircraft maintained for the controls to work ‘directionally correct’ means I’m processing a lot compared to KAP where I can feel if downwind and up is working, there is no such ‘feel’ with SUA.

So the powerful sense of connection with the camera I have through the flying line is something I have become accustomed to and is missing with the drone. The sense of scale, separation and abstraction is however much the same: I saw the trace of the roddden through the viewfinder and had the same sense of wonder as I tracked the drone back to me as I had with my first aerial views by kite. The world from nearspace is a beautiful thing:

I have been reluctant to get aboard the SUA bus as I feel aerial photography by kite has an inherrent joy and simplicity which sets it apart from other methods. I still feel this is so but the reliability of SUA operation, once I have my CAA ticket, makes it a tool I cannot ignore.

B

About billboyheritagesurvey

Heritage worker
Gallery | This entry was posted in KAP, SUA photography, Survey Practice and tagged , , , , . Bookmark the permalink.

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