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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 11 2012

Herbert Run West Surveying & Keystone Rental -- Updates

Saturday April 7th, Shelby and I went out to Herbert Run to stake out some more points on the western portion. We were able to get seven points that are all in the area pictured on the left. A lot of this area was really difficult to get because of the amount of brush that was online but we were able to get them all from a one of the new points that Will had RTK GPS located.

I went to Keystone Precision this morning to ask about renting data collectors, it turns out that they do rent out data collectors and they also give out software packages for them. The rates seem fairly inexpensive at $42.50/day, but they do not rent out prisms. I explained our situation and the sales representative generously said they would let us borrow a prism if we rented the data collector.

The data collectors are called the Ranger, which has a software package called Survey Controller and the TSC2  which has a software package called Survey Pro.

They also had an option to rent an entire total station plus rod set up for $120/day.

The representative at Keystone said that if I were to talk to Brian Wagaman I would be able to have a lot of my questions, (such as information pertaining to the stake out options of the data collector ) , answered.  I vaguely remember the survey company that I used to work for, Landesign Inc, were really big fans of Brian Wagaman’s help with total station questions and data collector trouble shooting issues, he is really approachable.

I believe this is the best way to proceed and hopefully we can rent the data collector and software for this weekend so that I can finish Herbert Run and the Knoll. I can call Brian tomorrow about the data collector rental and hash out the issues with him.

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 27 2012

Topography and the Mapping Grid

There has been a new data sheet designed to address the specific needs of the forest we are working with. Because the method for mapping the trees has changed, the data sheets also needed to be altered. We are returning to the previous used method of laying out a 1x1 meter grid within our 5x5 meter grid. Once this is complete the location of the trees will be marked on the graph found on the data sheet. There has also been a "codes" column added to the data sheet to represent trees that may need special attention. This could include a leaning stem, a stem broken below breast hight, or as seen in the picture multiple stems from one trunk forming below breast height. However, before the trees can be mapped the grid must first be sectioned into 5x5 meter squares. Jonathan, fellow students, and I are hoping to get one of the 25x25 meter plots sectioned off so we can begin to test our tree mapping stratgies. We are also tackling the problems we may face concerning drastic elevation changes. In summary we have all of our supplies ready and in bags we just need to find a time to get dirty and see how our ideas work.


 

Mar 07 2012

Finishing the survey grid

There have been many issues that have presented themselves while trying to survey this particular section of woods. There are many drastic elevation changes and two of our points appear to lie in the middle of the only small stream found in this section of forest. The surveying must be completed before the trees start to bud otherwise visibility would be virtually impossible to obtain, this being chief issue with the completion of the survey grid. When there is an accurate survey point set we can only plot a half a dozen points before needing a new point to shoot from due to visibility issues. Initially we discovered a way to make a new reference point through resection however Andrew and I soon discovered this was not an accurate enough approach to finishing the grid. A few more reference points must be measured before the grid can be completed and tree marking begins. An accurate effective method of tree marking must be used and we are in the process of obtaining Dr. Richard Condit's Tropical Forest Census Plots: Methods and Results from Barro Colorado Island, Panama and a Comparison with Other Plots. Hopefully this will give us a new outlook on how to plot the trees in the most precise manner.

Feb 14 2012

Surveying Friday 02/10/2012 with Kelly and Eric.

Today Eric and Kelly were able to accompany me in the field work. While we were out we were able to get 3 points layed out, determine a need for extra control and trouble shoot with instrument operations.

Surveying the first two points went just fine, but after the first two were staked out, I ran into a technical error that is best explained as the instrument was telling me to put the points in the wrong place 61 degrees away from where the points were supposed to go. It seems that whenever I want to re-establish my base line of 0 degrees, this particular instrument does not want me to do that. The only way to re-establish my baseline, or the line that I base all the other measurements with, is by completely re-entering the baseline station data. From now on this is what I will do to keep from wasting any more time.

Never the less we were able to stake-out three more points on the far east side of the Herbert run site. We had to do an offset for point number 152 because it was in the stream. What we did to obtain this point were two offsets one 7.12 m off of the point on the east side of the stream and another 2.68m off of the point on the west side of the stream. These two points are in line with each other and  if you pull an meter tape from one point toward the other the given distance for the offset you will be right on top of the point.

The first point 146 on the tree sampling grid, which was staked out the Friday 02/03/2012 prior to this one ended up 7 cm off. I am going to go ahead and wait till the grid is complete to restake this point out because it might be able to use a measuring tape instead of the total station.

Apr 05 2011

Digitizing Field Collections

Within the past few weeks digitizing the field collections was completed, this was accomplished by taking Jonathan and Evan's collected field data and creating a referenced shape file over the area of Herbert Run. The work was split by Mariah and I, in the picture above her points are green, mine are yellow. The data was in the form of hand-drawn grids and estimated point positions within the subplot were numbered including the species and estimated DBH of the described tree.

    The method I used in creating this representative tree population distribution is fairly straight forward. Each subplot drawing was overlaid with a transparency in which I attempted to equally partition the cell into 25, 5x5 meter subcells. A 5x5 meter subgrid polygon file was supplied for the Herbert run area and the drawn points were transferred.

 One of the main issues with the supplied data that may cause minor error was the case of trees that split at the trunk. These were denoted on the drawn grids as two dots, and frequently interpreted as two separate trees in very close proximity, rather than the same tree with two DBH's. This data can be fixed but its overall error effect on canopy data may be negligible.

  It's useful to note again that these points are NOT the true locations of the trees, but this set gives a representation of where the species occur. The next major step of this dataset will be collecting the heights of the given trees with the laser hypsometer, or collecting the data in 5 x 5 meter cells or both....we'll see which technique proves fit in the coming weeks!

Mar 05 2011

Field Day with the 485 Class

We had a great field day with the GES 485 class on Saturday flying the Hexakopter at the Herbert Run site and developing field work and 'ground-synthing' techniques.

The weather was actually quite good for a data collection.  The sky was overcast and there was no wind, meaning that the Hexakopter was able to stay on track and the light was relatively diffuse so there are few shadows in the images.  I gave a large set of about 2000 photos to Photoscan for processing on Saturday afternoon and it is still running.  This is a great software, but I don't yet have enough of my own benchmarking data with large sets to really test out how it is going to work. I hope the point cloud looks good!

Regarding our Xbee testing, I used the MKUSB to upload waypoints, but then discovered that when I power down and then power back up to swap out the battery and plug in the wireless Xbee module I cannot read waypoints from the MK, or they are not stored on board.  But, I was able to upload waypoints wirelessly with the new Xbee configuration and the real-time telemetry communication during the flight was OK.  At least the current setup is no worse than what we had before.  More to come.

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?

Dec 08 2010

Final Progress Report Fall 2010

Red = Un-measureable

Green = Tree Data collected

The past week or so have been very busy around school so only a little bit of time was able to be dedicated to actual data collection, but some progress was made. At this point in the season I find it very difficult to identify many of the trees due to their lack of foliage, but some of the tree’s bark has made this relatively easy. For this reason I have made the decision to most likely end my data collection (at least tree species) for the remainder of the year to avoid botching any data.

Another important aspect of this week was the data entry, which hadn’t been caught up in several weeks as most of my time was spent outside. The data has now been entered and organized by plot number to allow for easy reading. I hope to begin to compile statistics about the tree data this week with the help of Jonathan.