We have moved! Please visit us at ANTHROECOLOGY.ORG. This website is for archival purposes only.


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. 

Jun 28 2011

Automated terrestrial multispectral scanning

3D scanning just keeps getting better (but not cheaper!).

A post from Engadget: Topcon's IP-S2 Lite (~$300K) creates panoramic maps in 3D, spots every bump in the road (video) http://www.engadget.com/2011/06/28/topcons-ip-s2-lite-creates-panoramic-maps-in-3d-spots-every-bu/.

More from Topcon:

http://www.topconpositioning.com/products/mobile-mapping/ip-s2

http://global.topcon.com/news/20091204-4285.html

 

In China recently, we had the good fortune to collaborate in using a wonderful new ground-based (terrestrial) LiDAR scanner (TLS) from Riegl: The VZ-400, which fuzes LiDAR scans with images acquired from a digital camera (~$140K). Pictured at left- graduate students of the Chinese Academy of Forestry with us in the field- literally!

Mar 03 2011

New Field Equipment for 3D Forestry

Our new forestry mapping equipment is going to make collecting 3D tree and canopy data a lot easier!

We recently acquired a Trimble GeoXT GPS and TruPulse 360B laser range-finder for use in our forestry field data collection work.  The GeoXT is a high grade mobile-mapping, mobile GIS, GPS unit that offers sub-meter accuracy after post-processing in the lab. 

By itself this would allow us to collect sub-meter (0.5m – 0.7m) accurate positions of tree trunks or other features on the ground.  The TruPulse is used for measuring distances and heights using a built in laser and inclinometer that automatically does all that pesky math that would be needed when using an analog clinometer.  The 360B model has built in Bluetooth communication, which means that with a little configuration in the lab the unit can wirelessly beam positional and height data to the GeoXT.

This combo is used for ‘offset-mapping’ where the user stands in one location with both GPS and laser in hand and by using the laser is able to map to the GPS the XYZ position of other objects that are not nearby (typically less than 200m based on the power of the laser).  For us, this means I can map the position of tree tops in 3D space and automatically record the tree height to the mapping GPS with relative ease and greater precision than when using paper and pencil field notes.  This type of data collection is necessary for the calibration and validation of Ecosynth 3D point clouds, http://ecotope.org/ecosynth/methods/ecology/.

We will roll out this tech in the field in the coming few weeks as we move into the growing season, but in the mean time my initial results suggest that this will be a high-quality approach for mapping the position of tree crowns, a vital and challenging task.

The photo below doesn’t look like much, but it shows a sample of some of this 3D data.  This is an oblique shot looking through a 3D point cloud of the Knoll at UMBC.  The yellow area at the bottom is a digital terrain model of the land underneath the canopy; the blue points are the Ecosynth 3D point cloud of the site; and the red points are 3D points of tree tops and tree base mapped using the GPS  / laser combination.  This screen capture doesn’t do it justice, but trust me when I say that it looks good in 3D!

Hey Evan, are you sure you don’t want to come back to continue the forestry work?