Posted on June 21, 2013 by Howard Oh
This morning I started out to try and push a multispectral camera on any platform. Greg told me that a flight was just uploaded onto the NAZ but has not been processed yet. Since I was already out on the field I decided to try and create a sample of my own and try to get the Hala (Hawaiian Screwpine) classified differently from other vegetation just from RGB True Color images. Of the 3 Phantom quadcopters, 2 were being used out on the field and 1 was left but it was the one that was having problems. I decided to give it a try anyways and after Paul told me some of the problems it had I decided to practice at low elevations before trying to take it out onto the field for actual data collection. After some testing we decided that it was okay to be used out on the field because the quadcopter’s take off was okay and the slight lateral movement was minimal and was able to be controlled. With this information I geared up and went on foot to try and find the first area with a decent amount of Hala trees.
As I was searching for an area, I collected some points along the riparian corridor of more native trees. Usually this would be easy but the cattle were grazing a section of that field today and it was really tense walking in a field of cows just staring at me. I knew it was a tense situation because the baby calves were near the road I had to walk down and the some of the cows were getting very defensive. Some of them were curious and started to approach me. For some time I felt surrounded but I managed to slowly walk towards the other fence. The best area of Hala was on the south side valley and decided it would be a perfect location because the pyramid movie prop had a nice launching pad. I hike up there and find that one of the motors were dead. Right when I realized I had this problem it started to rain a lot and I had to quickly pack everything up. I ended up running to the nearest tree with some shelter from the rain. After waiting around 30 minutes I had to hike back to base. Fortunately another quadcopter was available with Emily’s help I got a ride and quickly went back to the location with Briton. I’m very glad he came with me because the first flight started to have problems. Since I was so close to the valley wall, during mid-flight the quadcopter lost some satellites and started to go crazy. It created bigger and bigger circles as I was trying to land it and it almost hit the pyramid! At the same time Briton was running around trying to catch it and injured himself on the deteriorating pyramid and the quadcopter blades. The 2nd flight was better and was able to get some imagery at a higher altitude. A slight problem I had was when the winds picked up the quadcopter and made it continue to climb higher and further away from me. I tried getting the quadcopter to fight the wind to come back and barely got it back in time ~ 5 minutes and 45 seconds. Again, Briton helped me by grabbing the copter mid air just as it was running out of juice. I spent the rest of the day cleaning up my attribute table for the points I collected and going to make a mosaic of the images I got and first try to see if I can separate out any of the vegetation through a simple ERDAS supervised classification. Here is a sample of the imagery I got.
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