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May 05 2012

Presenting Herbert Run 25 meter grid!

Today Darryl Wise joined me and we went out to finish Herbert Run. It went smoothly and we were able to finish all the points except for one that was under and a car and one that was about a foot under water right in the middle of Herbert Run. What I would like to do now upload the points onto the computer using ArcGIS and this would possibly enable me to view the shots that I have taken in a saved data base. With the points that are in the stream, both 162 and 169 I could come out the day of the tree mapping and provide consultation about where the exact location of the point would be. There are also two off sets to each point, each of which I have recorded. 

Now that Herbert Run is finished I can start on the Knoll, May 11th 2012. The first thing that I will do is create a network of control points. When that is finished I will Start the stake out of the area. I think the Knoll is contained a little more than Herbert Run is therefore it should be topographically easier to survey.

With the use of the data collector and a solid understanding of how the survey will procede I will be able to finish The Knoll magnitudes of time faster than Herbert Run with out a doubt.

One cool thing I want to note about all this surveying that I have been doing is that all these control points that I am using are good control points that could be added to the schools data base of established control. I am not sure if an actual PLS (professional land surveyor) would need to sign of on the authorization of what is "established control" or basically just the legitimacy of the control points.

May 02 2012

Update on Herbert Run Survey

Friday and Saturday the fourth and fifth of May will be my last two days to Survey HR. Last weekend during the tree mapping party I was able to get most of the remaining points in Herbert Run but there will be two control points worth of stake-out left. I was also able to complete a traverse loop that consisted of 10 traverse and will figure out how to find the closure on them this week. As seen on the left are the remaining points in Herbert Run that still need to be surveyed. It is only about seven or eight. In order to stake out the last few points I will only need to make two more control points. Once those control points are set I will get three points from each set up. There is a chance I will need to make one extra traverse in order to obtain some points that are located near the street.

Once Herbert Run is done being surveyed I will be able to work on the Knoll. The Knoll will take way less time than Herbert Run did because I will be doing most of it during the Summer time when I have a lot more free time and also I will have the data collector. I am guessing i will be able to do about 5 points/day and in a 40 point grid that is 8 days.

I expect the whole survey which includes Herbert Run and The Knoll to take up till June 16th at the absolute latest. This is accounting for the fact that I will not always be able to find some one to help me Survey seeing as how it will be the beginning of summer vacation. I am guessing I will have some one available roughly three days/week.

Apr 25 2012

Finishing up Herbert Run

Saturday April 21st  , Shelby, Dana and I went out to Herbert Run and were able to get a lot done in in the field. We were able to set a decent amount of control points as well as make progress during the stake-out by obtaining roughly 8 more points. The points we were able to get were the ones on the far Eastern edge of Herbert Run 168-175. This leaves us with about 8 or so points left that need to be mapped out and I am convinced that with Dana's help today and a little help Friday that I will be able to complete the Survey either Saturday or Sunday at Herbert Run. Then next week I can do the complete Survey for The Knoll.

This data collector is helping a lot. At Landesign Inc. the data collector I used was no where near as nice as this one is. It can connect to the internet, which could make stake out really convenient. As displayed in the picture on the left the Trimble actually pulls up a complete map of the Survey that I will do. The points you see on the screen are the ones that I have loaded in. It also has my control points which you can see towards the top left of the screen as point numbers 4004 and 4005 These are my traverse 1 and traverse 2. This will be how I establish my traverse loop which because of the small size will probably have quite a small amount of error.

I am considering using existing control at Herbert Run to create control at the Knoll. Since I have specific coordinates for the traverse at Herbert Run I can use those to Run control down to The Knoll. This just means that I will have two traverse loops obviously the one that connects HR to the Knoll is far larger than the one that will be specifically for HR, which entails more error but we can distribute that error evenly throughout the loop and it will be fine.

Finally I am going to need to create the Grid points in GIS this week for The Knoll so that Monday I can get started on that.

Dana also had a great idea when we were out in the field she proposed that we use the GPS to guide us to the points that we are trying to survey. Sometimes these points are in the worst locations such as the points around 170 in Herbert Run and it can be a major hassle trying to read the map and decide what direction and how far is needed to pace to the next point. With the GPS we could get a much better rough estimate of where the next point to be staked out is, for those points that when using the map and actually walking through the forest are impossible to just pace to. This is the situation for large fallen trees in the way, large increases in elevation and streams.

Apr 17 2012

Rendezvous with Brian Wagaman

I was able to get in touch with Brian Wagaman on Friday April, 13th 2012. What we had landed on was that I will meet him at Keystone precision on April 19th, 2012. I sent Brian Wagaman an email of Dr. Ellis email regarding billing for the data collector rental. When we get together on Friday Brian has agreed to instruct me on how to establish a network of control points via the traverse method with the data collectors that Keystone has available. This instruction will be completely free, the only charges will be for those of the data collector. I was going to ask if it is ok to take the instrument home Friday at the meeting Wednesday, Brian and I will use it for a couple hours then on Saturday I will work a twelve hour day Surveying the Bananas out of Herbert Run. I will need two volunteers for two shifts because I do not think anyone person should have to help me for more than six hours. the week following that I will have a gap between exams that will allow me to do the Knoll so it would be best to rent the data collector from Friday April,19th 2012 up till Monday April 30th that way I will definitely have ample time to finish the survey. 

I believe that this will dramatically increase productivity because I will not have to wait on control points. It will speed up the process ten fold. The survey of both the Knoll and Herbert Run should be complete by 4/30/2012.

I could have met up with Brian on Monday but I was swamped with two exams this week therefore I thought it would be best to rent the data collector for a short amount of time instead of just having it while paying for it and not actually using it for any surveying work.

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.

Nov 22 2011

Analyzing the Point Cloud Transformations

This graph represents the data for the Herbert Run site from October 11, 2010. I used ScanView to locate the exact coordinates of the orange buckets in the transformed point cloud that was created with the previously written helmert code. The values on the X-Axis represent the actual GPS values from the georeferencing in the x direction, where higher values are more western, I believe. The values on the Y-Axis correspond to the calculated mean of the orange points I extracted with ScanView. The black line is the line of best fit of the data and has a slope of 0.9941, which is quite close to 1. A slope of 1 would indicate an exact correlation between the two data sets. This is good in two ways: the slope is actually positive, so there's a positive correlation between the two data sets, and the slope is very close to 1, which means the correlation is strong. The graph for the Y values is very similar, with a positive slope of 1.0079. What's really good about this is the results I got before I did this analysis, with the point cloud of a different data set.

This is for the knoll site from fall 2010. There is a negative correlation, and the slope is no where close to 1, so this mean the transformation of this particular point cloud did not turn out well at all. It's possible that I made a mistake running the spline.py code to get the 7 Helmert parameters. The 4th parameter which is for scaling was negative which doesn't seem nice, but it looked like the data wasn't rotated enough either. I still have another data set to test out, and once that is done I'm going to retry this data set to see if it was just a mistake I made.

A small note about the bucket search based on colors, some of the buckets were on top of blue boxes which seemed to be altering the color of the orange points, they looked pretty pink which was not a color I was searching for. This could be a reason why some of the buckets were not registering in my search. Plus Jonathan pointed out that some of the trees were starting to change colors at this point, so that could be a small source of some of the extraneous points.

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?

Feb 25 2011

Photoscan is awesome!

Agisoft’s Photoscansoftware is simply amazing!

The picture at left is an orthorectified photo mosaic over our Knoll research site on the UMBC campus generated by Photoscan automatically using only input photos that I took with the Hexakopter.  For reference, each Hexakopter photo covered less than a 10th of the area observed in this scene. 

An orthophoto is a photo that has been mathematically distorted based on the differences in elevation of the scene so that everything appears ‘flat’, or it appears that the camera was right above each point in the photo.

Photoscan uses similar computer vision technology that Bundler and Photosynth use to automatically recreate the 3D structure of a scene from only photos.

The professional version of the software also makes it very easy to georeference the scene to a geographic coordinate system, making it possible to easily view in a GIS software … or in Google Earth.

Here is a link to a Google Earth image file that Photoscan generated from our photo set, enjoy (35MB kmz file)! 

I am working on getting some 3D output to Google Earth next.

Oct 29 2010

Field Work Progress Report

So far this week I was able to put in a couple of hours to continue the field work that was initially laid out by me and Noam Raffel over the Summer of 2010. The tree plots of Herbert Run near completion with what appears to be perhaps another week or two’s worth of work, barring any complications with weather, etc. The leaves are changing quickly at this site as can be seen from the bi-weekly photos taken by Jonathan and the team so this has made it exceptionally apparent that it is now or never (at least not until spring) for the field work.

The measurements are coming along nicely especially since we began using the 3P mode on the hypsometer to limit the distance we have to stand from the tree for accurate assessments. This function works more similar to a clinometer than a standard range finder as 2PL mode does. Several plots worth of trees should be measured using both modes to ensure the consistency of the data.


Diagram of Plots

Red = Un-measureable due to new fence

Green = Tree Data collected

Yellow = Remaining plots





Check back to this blog for weekly updates on the progress of our field work and comparisons to the data we pull from our photos!

Oct 19 2010

3D and Spectral Remote Sensing with Computer Vision

Wow, what amazing progress!  I posted a few weeks ago when we were just starting to get the Hexakopters working, how excited I was when I considered that we were still flying kites just ONE YEAR AGO!  Now it is becoming a reality that the Mikrokopters can really move this interdisciplinary research fusion of ecological remote sensing and computer vision into a reliable system for making 3D, spectral color measurements of ecosystem vegetation for measuring biomass and species diversity.  

There is definitely a lot to learn about the process, but we have got the flying down pretty well for data collection.  The video here is of me flying the Hexa up through a large gap in the canopy at the Knoll site at UMBC.  This is an invaluable capability of this system (and its pilot!) that makes it possible to fly sites like the Knoll and SERC, where it is not possible to be centrally located in a large open clearing.  

DRAFT: comparison at HR sites, seasons