May 02 2012

First Group Field Day

On Saturday 4/29/2012 we had the first field day of the semester. The goal was to begin mapping the trees at HR and to perfect our methods. However we soon discovered that our 5x5 meter plots that had been previously marked with PVC had much more error than we anticipated. To accommodate this we mapped the trees in the corners of 25x25 meter plots because they contained the known survey points.

We managed to get 8 of the 5x5 Meter plots surveyed and ready to document. Also, we have determined a new method to plot the 5x5 meter subplots. Our error came from one main source. When we were measuring the 5x5 subplots we started by marking the perimeter. Once this was done we laid out a string across the plot and measured along the string to mark our subplot points. While the points were 5 meters apart in one direction they were not in the other. The reference string did not provide enough accuracy and would lead to a line of points which fall to the left or the right of where they should fall.

To tackle this problem we purchased a straight line laser that can shoot up to 1000ft. The idea behind this is it will give us a perfectly straight reference line. We will shoot the laser across the plot from one known perimeter point to the next and than proceed to mark the points within the plot that lay on this line. This will hopefully do away with the error that accumulates while measuring along an inaccurate reference line.

At the end of the day we learned allot about our methods and what needs to be improved. This is all a part of field work to design, test, and redesign. Hopefully we will have another group field day soon with corrected subplots allowing much more mapping to be accomplished. I want to thank everyone from the ecosynth team and volunteers who made this day possible. 

Apr 02 2012

Surveying The west side of HR

On Saturday March,31,2012 Dana and Shelby joined me in the field for a day of Land Surveying. Will Wiley was not able to come out this weekend and give us the points that we need to finish the survey but In the mean time Jonathan and I had decided it best to use this bottle neck as an opportunity to get the west side of the site done. We started with the points that were near the dam and moved East Until we ended up adjacent to the east side of the grid. We were able to get 18 points done that day between the three of us which leaves only 22 points left for this part of the grid. I will email Will Wiley again after this Wednesdays Ecosynth meeting to get an update about when a good time for him to go out to the field would be.The weather that day was really nice it was a bit over cast ( I managed to get a tan though!) and it stayed relatively calm with respect to the wind. This calmness made some of the points easier to get.Point number 102, in the thick of the brush, would have been nearly impossible on a really windy day. I really appreciated having two people out in the field to help me it seemed like things were able to go alot smoother just because we had extra hands to carry things. The point that seems to be in the middle of the dam 111 I did not put in because it seems like the contractors will come and clean that dam out periodically and it seemed futile to actually put this point down because of the constant grade changes that are likely to happen here. Hopefull we can finish the rest of the grid this weekend and have WIlls help this weekend also to get some new control points.

 

 

 

 

 

Mar 21 2012

Tree mapping Technique

There have been many methods for mapping the trees within our 25x25 meter grid that we have identified. The one certatinty we have decided on is the grid must be sectioned into a 5x5 meter grid before we can begin mapping. The picture on the left shows a method found in the field guide Methods For Establishment And Inventory Of Permanent Plots. This method involves usining geometry to determine the exact point of a tree and we thought it could be more accurate and faster than other ideas. However when we went to our forrest to test we discovered that it was not only more tedious but may not improve accuracy by a reasonable amount if at all. The problems arose when we needed to take measurments on unlevel surfaces. It would involve 3 or more people with much instruction and using handfulls of equpment, it was uneffective for our purposes. We plan on going on another test run before the week ends to try another method that will hopefully work for what we need. 

References:

Dallmeier, F. (1992). "Long-term monitoring of biological diversity in tropical forest areas." Methods for establishment and inventory of permanent plots. MAB Digest Series, 11. UNESCO. Paris

Nov 17 2011

The Algorithmic Beauty of Plants


In searching for research related to the structure and architecture of trees and canopies, I came upon the book The Algorithmic Beauty of Plants and the research of Dr. Przemyslaw Prusinkiewicz and his Algorithmic Botany lab in the Department of Computer Science at the University of Calgary.  All I can say is, 'Wow!'

The image at left is from a 2009 paper on procedural, self-organizing reconstructions of tree and forest landscapes.

Dr. Prusinkiewicz's research spans over two decades and his website includes published algorithms for procedurally generating 3D, colored, and textured plants.  Some of the figures in these papers look amazing.

I look forward to looking more into Dr. Prusinkiewicz's research for inspiration and insights in support of my own research with computer vision remote sensing based reconstruction of canopies.  Some of Prusinkiewicz's work covers the use of point clouds to 


represent tree structure, so I am definitly interested in learning more about that data model.

References & image credit:

Wojciech Palubicki, Kipp Horel, Steven Longay, Adam Runions, Brendan Lane, Radomir Mech, and Przemyslaw Prusinkiewicz. Self-organizing tree models for image synthesis. ACM Transactions on Graphics 28(3), 58:1-10, 2009.

Oct 25 2011

CAO Dreaming

Breakthrough technology enables 3D mapping of rainforests, tree by tree” - the latest news from the Carnegie Airborne Observatory (CAO)- but also old news: since about 2006, the CAO has been the most powerful 3D forest scanning system ever devised, and Greg Asner has continually improved it.

The CAO was the original inspiration behind Ecosynth.  In 2006/2007, I  was on sabbatical at the Department of Global Ecology at the Carnegie Institute of Washington at Stanford, and my office was right next to Greg’s.   Though he was mostly in Hawaii getting the CAO up and running, he and his team at Stanford completely sold me on the idea that the future of ecologically relevant remote sensing was multispectral 3D scanning (or better- hyperspectral- but one must start somewhere!). 

I coveted the CAO.   I wanted so much to use it to scan my research sites in China.  Our high-resolution ecological mapping efforts there had been so difficult and the 3D approach seemed to offer the chance to overcome so many of the challenges we faced. 

Yet it still seemed impossible to make it happen- gaining permission to fly a surveillance-grade remote sensing system over China?  It would take years and tremendous logistical and political obstacles to overcome.  So I changed my thinking…

What if we could fly over landscapes with a small hobbyist-grade remote controlled aircraft with a tiny LiDAR and a camera?  Alas, no, - LiDAR systems (high grade GPS + IMU) are way too heavy, and will be for a long time.

Then I saw Photosynth, and I thought- maybe that approach to generating 3D scans from multiple photographs might allow us to scan landscapes on demand without major logistical hassles?  The answer is yes, and the result, translated into reality by Jonathan Dandois, is Ecosynth.

Can Ecosynth achieve capabilities similar to CAO?  Our ultimate goal is to find out.   And make it cheap and accessible to all- as the first “personal” remote sensing system of the Anthropocene.

Jul 09 2011

Leafsnap: An Electronic Field Guide

image

Yet another dimension of computer vision...

Leafsnap:

“ is the first in a series of electronic field guides being developed by researchers from Columbia University, the University of Maryland, and the Smithsonian Institution. This free mobile app uses visual recognition software to help identify tree species from photographs of their leaves. Leafsnap contains beautiful high-resolution images of leaves, flowers, fruit, petiole, seeds, and bark. Leafsnap currently includes the trees of New York City and Washington, D.C., and will soon grow to include the trees of the entire continental United States. This website shows the tree species included in Leafsnap, the collections of its users, and the team of research volunteers working to produce it."