Public Lab Research note


First YouthCaN Trial Kite Mapping

by jholmes5 | June 23, 2013 13:22 | 38 views | 1 comments | #8391 | 38 views | 1 comments | #8391 23 Jun 13:22

Read more: publiclab.org/n/8391


June 22, 2013 Prospect Park, Long Meadow, Brooklyn, NY

Working with students on mapping:

What I want to do

Learn how kite mapping works through hands-on learning. What are some of the challenges and how to succeed.

My attempt and results

The folks from the NYC PLOTS community loaned me a kite and a camera (Canon A495 with program for timed shutter release) with and rig.

Our activity was part of a visit to the Brooklyn Botanic Garden visit followed by some practice kite mapping in Prospect Park. The participants in the program were to be a group of high school students who participate in a program called YouthCaN (Youth Communicating and Networking) at the American Museum of Natural History http://www.youthcanworld.org/ . The plan was that this would be a first exposure (no pun intended) to mapping and that the students might develop an interest in applying this to some of the environmental projects that they are involved in.

Challenges for me were pulling together all of the gear, this problem was solved by Liz Barry and Veronica from the PLOTS team. They were VERY helpful and we managed to hand off all of the gear. This was something of an add on to the BBG trip that I thought might be a fun introduction for the students, so it sort of developed a little late in the time line of developing the trip. But Liz and Veronica jumped in fast and all of the gear was collected, I had a chance to test and practice assembly in my apartment and was ready to go on the day.

Challenge two: No kids... that was a bit of a disappointment... I am not exactly sure what happened with that. We were expecting 8 students, but none showed up. We had three adults and one 5 year old. This group is part of a project that is in its 20th year, we usually have a better turnout. There have been some staff turn over in the last two years so we are working on rebuilding a little... it was a beautiful day, first Saturday of summer... family activities may have taken priority.

Results: Low winds at first had us grounded. Tried test flights with just kite, then kite and tail. Inconsistent wind had us up and down a few times. So we chatted about students and planning and waited. The winds started to pick up so we arranged the camera rig and got the kite up. Once we were above the tree tops, all was beautiful. The camera was swinging a fair amount, and stable at other times. This turned out to be very helpful for me. I was not sure of the field of view for the camera. As it turned out it was a bit narrower than I expected, and the swinging gave us some shots of the edges of our lawn area, trees, water and the Picnic House.

I consider this expedition a success for myself because I became familiar with the tools and some of the challenges and have some ideas for a more successful second flight.

Questions and next steps

1) Is the zoom setting on the A495 set a little long to reduce barrel distortion of a wide angle shot? Is this something beneficial for mapping purposes?

2) Seems like a lot of blur in most of the images, but the shutter speed was fairly fast. I did not use the "wings" which may have helped with stability. And the rig was just hanging from a single string so there was lots of spin... next time I will hang the gig from two points.

3) Some of the blur seemed to be focus related not camera motion related. I wonder if there is a way to program the camera to just focus at infinity or something close to it since the kite to ground distance is so great. Perhaps a smaller aperture (higher f-stop) would give enough depth of field so focusing would not be needed. This might give a slower shutter speed, but the ISO on the A495 was pretty low (It think it was 80). It could be bumped up a bit, unless the camera has a limited ISO.

Next steps: My own kites are in the mail somewhere. Will probably arrive next week. (Priority mail does not seem to be much faster than regular ground...)

Have a couple ideas for cameras of my own.

We will try this again with the students on a future expedition and see how they respond. Photos and a report of yesterday's outing have been shared through an online forum and hopefully that will entice a few to come out and explore next time. I will try to work more closely with the students to see what challenge we face with getting them out.

Jay Holmes New York City, New York

Trees_Lake_Lawn.jpg


1 Comments

This sounds like an excellent first outing. There are some tips for using the A495 for aerial shots here (http://publiclab.org/wiki/canon-a495-tips) including infinity focus mode. There is a tip about using CHDK to keep the shutter speed high at the bottom of the page here (http://publiclab.org/wiki/dual-camera-kit-software), but the speeds of your shots (1/400 and 1/800) are good. Reducing camera swing is a good goal. Some Powershots have wider angle lenses than the A495, but not by much. The A495 field of view is a very useful compromise for mapping and general aerial shots.

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