Skip to Local Navigation
Skip to Content
California State University, Long Beach
CSULB Geospatial Research and Mapping (GRAM) Field Program
Print this pageAdd this page to your favoritesSelect a font sizeSelect a small fontSelect a medium fontSelect a large font

Daily Blog for Howard Oh

Day 27

Posted on June 29, 2013 by Howard Oh

Today our tasks were:

1. Cleaning up and uploading our data

2. Filling our the questionnaire

3. Sharing photos/other data on the NAZ and dropbox

4.Pack up and get ready for our 2210 flight back to LAX.

Day 26

Posted on June 29, 2013 by Howard Oh

A lot of people were on edge just waiting until it was our presentation time. I did approximately 4 to 5 full practices of my presentation landing at around 9 to 10 minutes 20 seconds. We got dress as professionally as we could and headed to Kualoa Ranch. Long story short, everyone gave their presentations to a good sized crowd of anthropology students, professors, graduate students and Kualoa staff. Many of them said we did great as a group concisely presenting our research. Afterwards we headed to a nice restaurant and got some small plates to share. When we got back to the ranch some people did some work and some people just needed to relax and have some downtime.


Day 25

Posted on June 28, 2013 by Howard Oh

Today mostly everyone was in the barn for most of the day working on papers and presentations. I called it quits after 2 a.m. so that I’ll have enough energy to deliver a presentation tomorrow. I won’t share any pictures yet because I do not want to give away my presentation. It will all be posted soon to our NSF-REU wiki page.

Day 24

Posted on June 27, 2013 by Howard Oh

Because of all the problems I have been having with the mosaics and processing time in eCognition, I have decided to focus my native plant classification methods to single RICOH images taken off of the X8. I worked first on the RGB image that had a good location of Hala and Kukui. With using powerful tools like texture to differentiate vegetation types like pasture and mixed vegetation I had good results. The classification was able to separate out the Hala, Kukui, Soil, Mixed Vegetation and Pasture. It took some time to find the right settings but I was surprised at how well it came out.

Day 23

Posted on June 27, 2013 by Howard Oh

After a late night discussion with many REU students and grad students (especially Emily!) I had a new mission. Everyone helped me brainstorm throughout the whole day and Emily helped me focus on another area that may possibly have different vegetation growing on opposite sides of the area we call Narnia. I was still continuing my idea of trying to classify some native plants versus non-native plants but with a new focus on trying to correlate the vegetation with geology. With this new focus I headed back out to the field with Paul and got a phantom going. It was raining for most of the morning and I was concerned that I was not going to be able to fly the quadcopter and get the imagery I needed, again. Luckily the sky cleared up and we had a window in between rain clouds to get about 6 good flights in with good ground cover. Back at the barn, I stitched the imagery and saw that it had good coverage. The problems I faced were when I downloaded my XY points from a handheld GPS. Because of the dense canopy cover, some of my points were off my 10 meters. The tree I thought I may classify separately was the Banyan tree because of its distinct canopy cover. However, when I looked at the imagery it looked very similar to the Koa Haole and in some parts of the image, it was difficult to differentiate between plant species, especially when my ground truth points were not accurate. Even eCognition had a difficult time correctly segmenting out the separate tree canopies.

Back at the barn, Dr. Wechsler gave me more insight on the aquifers and DEM data and how they might be a factor to the vegetation in the area. She also helped me get in touch with Dr. Becker and he also enlightened me that the soils were more of an important focus and had a stronger correlation to the vegetation. There was also the idea of trying to map out areas with different salinity and see if some plants were more dominant than others in either fresh, salt or brackish water. Unfortunately, I was unable to find usable imagery in that area to get down to the species level classification for that type of analysis.

Day 22

Posted on June 27, 2013 by Howard Oh

Today I had to reassess my research and really hone in on some analysis with the imagery and tools available to me. I was hoping to get some really cool multispectral imagery but from being out in the field I realized how difficult it actually is to obtain. In the Ka’a'awa Valley the weather is unpredictable and the rain and wind make it difficult to get flights in for both fixed wing and helicopter UAVs. Because of this challenge I was not able to compile a full stitched image of the valley and had to think of sample areas. I’ve come to find out that even a photoscan of 30 images with high settings for geometry and texture can crash my computer. I also had trouble stitching the imagery because the GPS camera did not have ideal satellites and logged the same coordinates for multiple images. It wasn’t too much of a problem but better XY data makes things a little easier. Much of my time was spent merely stitching imagery together and seeing what I could and could not use. There are still flights being attempted for the multispectral imagery and it would be nice if I could eventually use some for my analysis on the vegetation. For some reason my mosaic image of part of the south valley results in the image below. Paul and I were trying to figure out a solution but we had no luck. Even though photoscan displays the image properly as a flat rectangular surface, the exported TIFF becomes distorted in this shape. Because of this I will try to find another study site and use new imagery.

Day 21

Posted on June 26, 2013 by Howard Oh

Our free day started out with a bus ride to the Turtle Bay resort to get our rental car. Our goal was to full tour by driving around the entire island and we actually ended up doing it twice. The highlight of the day was going snorkeling with Greg and Peter at shark bay. At night we tried  to meet up everyone at Waikiki but ended up just shopping around the international market place and headed home.

Day 20

Posted on June 26, 2013 by Howard Oh

This day wasn’t so great because I did not get the results I wanted. I went out into the field again to try to get imagery of the area with a pretty good amount of Hala. The problem was that rain and wind got in the way of the flight plans and didn’t get me the images I wanted. I spent a lot of the time trying to stitch together the images I had and after waiting hours of building geometry and texture I got a product that I wasn’t really able to use. I lost a lot of time from my computer overheating and crashing, causing me to start it over again and try Photoscan on lower settings. Eventually I was able to stitch my photos off of Paul’s computer. We had another update/group discussion and when it was my turn to share my ideas were shot down and I was left to reassess my research question. I was really stressed out for the rest of the night and was fortunate that the next day was our day off. Hopefully I get to clear my mind and think of something. Today was the first day I didn’t take a real photo but here is one just to look at.

Day 19

Posted on June 22, 2013 by Howard Oh

Similar to yesterday I went back out into the field with a quadcopter and a pentax optio and tried to get imagery of the native plant Hala which grows near the ridge lines/ areas that have low disturbance. Much of the time the cloud cover, wind or rain delayed our flight and we were only able to get 2 flights in the whole morning and afternoon. I spent the entire night using photoscan and trying to mosaic my images to the best of my ability/computers ability. After dinner I also had the opportunity to talk to Mike the graduate student and Dr. Lee about what my actual focus would be. It is a good thing we talked because I wanted to focus on using UAV/UAS imagery while he was under the impression I was going to continue to work with the WV-2 Imagery.

Continuing my thesis research, I believe that satellite imagery is inherently disadvantaged to UAV/UAS imagery because of cloud cover, long re-visit times and low spatial resolution. Because of these disadvantages I believe the future in vegetation imagery is by using UAVs. Although they still lack the strong multispectral sensors in satellites, the higher spatial resolution is still currently better for a species level classification.

Day 18

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.

About Howard Oh

Senior at Cal State Long Beach studying Political Science and Geography/GIS