Week 4: Distance and Azimuth Survey

Introduction:
 One cannot always rely on technology to always be functioning perfectly. A backup device or plan is usually a good idea, for example when the first version of apple maps came out I'm sure those iPhone users wish they had a highway map instead. When out surveying landscapes the device you are using may not pick up a signal or just plain run out of battery, without use of that technology it could end up being more effective to go back to the bronze age of geographic surveying, a compass and ruler. For this week's activity we went out and surveyed a 1/4 hectacre plot of land using a TruPulse 360 azimuth, distance and elevation laser and we also used a compass and distance finder.

Methods:
 The study area my group chose to work with was based on the goal of surveying for 50 nodes. We chose a plot of land on 'upper campus' of University of Wisconsin - Eau Claire with a good amount of trees, Frisbee Golf holes, and other miscellaneous items found on a college campus.(Figure 4-1) Our geographical selection was a generally flat surface so we found our origin and got to surveying.
 The TruPulse 360 (Figure 4-2) is capable of emitting an invisible infrared energy pulse that determines the distance by measuring the time it takes for each pulse to travel to the target and back to the TruPulse. Once the measurement is complete, it is displayed on the viewing screen inside of the view hole. The readings can come back as slope distance, azimuth, inclination, horizontal distance and vertical distance. Our group made use of the horizontal distance and azimuth tools the TruPulse provided.  The other method we used was a compass and electronic distance finder. The distance finder was a two piece instrument that sent out a radio signal to the counterpart and returned and measured out the distance, much like the TruPulse, but with only one function and not nearly as fascinating.
 The compass we used was very accurate once adjusted for the declination. Magnetic declination is the angle between the compass north and the true north. Figure 4-3 shows and example of magnetic declination with a positive variation from geographic north. When the declination is affecting your measurements it is important to adjust the compass, there is usually a small screw to fix the issue. Luckily in Eau Claire, WI our declination is very minimal, 0 degrees and 59 min West, so we had only the slightest adjustment to make. The readings off the compass were made while holding the slit in the side of the compass up to one eye, while there you can see both your target and the reading of azimuth.
 Once we decided on the point of origin, just off the corner of Horan Hall, we began surveying points. I used the TruPulse while my partner recorded the measurements I was reading off. We had another group of colleagues alongside of us, they used the compass and distance finder and we later collaborated our efforts in completion of the activity. I used the TruPulse's capabilities to measure the azimuth and horizontal distance to each tree as we recorded across our 1/4 hectacre. Our group only found so many trees, and so we began recording readings to other features, garbage cans, emergency posts, signs, Frisbee Golf holes, and even a sign post.
 Once the surveying was done we entered the data into an Excel file. We had to make a field for the distance, azimuth, point data, and point number. (Figure4-4) Once the file was brought into ArcMap I set up a Geodatabase to house all the data. The table was exported and before I could run the Bearing Distance to Line tool I realized it was necessary to give each data point the point of origin for the surveying. Unfortunately we did not have a definite location for the survey location, as a result I went into ArcMap and opened the Bing Basemap and created a point feature class and created a point at the survey origin. Once the point was created I took the (x,y) data from the origin point and entered it into the Excel file for each point. When the new table was brought into the geodatabase the tool was completed. I ran the tool for each of the surveying that was done, the TruPulse and the compass with the distance finder.

Discussion:
 The accuracy of the results were difficult to compare, as our groups measured together we didn't stand in the same place of origin. This clearly threw our data off by a few degrees and meters here and there, we stood close together but the difference of a foot or two certainly had its toll on the results. (Figure 4-5) When I plotted the points there were issues with making the Bearing Distance to Line tool produce the results in the proper place. The original point of origin I made was done outside of a geodatabase with a non-defined spatial reference. The displacement of the result was close to the proper origin, but not close enough to call accurate to any measure. (Figure4-6)
 When viewing the results of the tool I took into question the accuracy of the entire methodology that we used. As you can see from Figure 4-4 the view that I had for the points on the bottom right corner of the image was not possible, how could I measure through the corner of the building. The other readings, red points, were done closer to the building and they had no issue getting measurements of the points in the bottom right corner of the image. Though none of the points are where they are supposed to be, (Figure 4-7) it is strange to see such a glaring inaccuracy with the TruPulse measurement methodology. The main issue is that the points are not where they are supposed to be, the blue points represent the actual location we were attempting to measure for, the Compass (red) are fairly close to where they are supposed to be considering the distance away from the origin they are. But the TruPulse points (green) are very far off from where they are supposed to be. However, from looking at these maps it is harder to detect the issue that arose, possibly it was measurement communication error, it could be error in the spatial reference. There are a handful of things it could have been.

Conclusion:
  Unfortunately our group was stifled with not enough nodes to measure, we got up to 32 but were unable to get accurate measurements of many others due to interference from previously measured nodes. Also another issue that I had was the inaccuracy of the data at the end of the activity, as I said before I would like to find the origin of this error. This activity was very useful in learning how to use surveying equipment and deducting the best way to record data that is taken. My only wish is that these few labs could be done when it is warm outside, I'm sure that would decrease all error that is arising.

Week 3: Construction of Balloon Mapping Equipment

Introduction:
 Nothing great comes without planning. Michael Jordan planned to be the best and worked harder than anyone else in basketball and succeeded. Man landing on the moon was years in the making. And filling a balloon with a camera apparatus attached to photograph campus is a process that took a few hours with 18 people working on it. The plan this week was to analyze schematics from multiple sources and come up with the best functioning apparatus to capture images of campus from a few hundred feet above ground.

Methods:
 The preparation for the balloon mapping project has gone hand in hand with the high altitude balloon launch (HABL). This week the class separated into separate groups to start producing and planning each necessary step for the launch date, which is still tentative at this point. People in the class split up for tasks such as:

• Construction of the mapping rig
• Construction of the HABL rig
• Parachute testing
• Payload weights of both HABL and mapping rig
• Design of implementing continuous shot on the cameras (for mapping rig)
• Implementation and testing of the tracking device
• Filling the balloon and securing it to each rig

 I was a part of a few of the tasks, there was a fair amount of people doing each one so I was able to help with each one for a fair amount of time. The mapping rig construction was created using a few 2-liter soda bottles. The plans we obtained from multiple online sources, here is one:

http://archive.publiclaboratory.org/download/Grassroots_Mapping_English_2_0.pdf

 This site shows all of the items you will need, along with the steps for creating the rig. The soda bottles were cut in half, keeping the neck and bottle cap section, so we could drop string through the top and have it hold the camera. The camera in the rig is only held by the string, so it dangles in the cut open soda bottle.(Figure 3-4) After completing the rig to hold the camera, we had to find a way to make the camera stay in continuous shot mode. My colleagues created a way to hold down the capture button on the camera with a tight rubber band and a piece of plastic on the top of the capture button. (Figure 3-1)
  While a group was working on the mapping rig there was another weighing each item that could or would be used. The group took weights of each individual item and recorded them into a table in excel. (Figure 3-2) It is important to have a precise weight of the payload so we know how much helium to pump into the balloon that will hold up the mapping rig, or the balloon that will take our camera to the top of our atmosphere.
  The parachute test consisted of a bait tackle box with a 2 lb weight inside of it, the projected weight of our payload. Our group went up to the fourth floor of Phillips Science Building and threw the tackle box out the window. (Figure 3-3) after doing the test three times we were pleased to find out the parachute worked properly.
  While the parachute test was being done another group went out and tested the tracking device. The PocketFinder gps device can send out its coordinates at different settings, every second, four seconds, 30 minutes or hour, we decided it would be best to do it every four seconds. The group went out for a walk and we could keep track of his location using the online application that maps out each point for you. This will be used in the HABL rig to help us find it once it lands.
  The HABL rig is still in development as we are going to wait until closer to the launch date to complete the project. We are planning on using a bait tackle box with a view hole cut into the bottom of it for a clear camera view. The camera will more than likely be in video mode as the pictures would be a little less exciting. The rig will consist of a sealed area with hand warmers which is where the camera will be situated in. The tackle box will be attached by a carabiner and string to the parachute and balloon as it rises. Once the balloon pops the payload will fall and it will be supported by the parachute.
Discussion:
 The project for the day was a good way to observe how well our class worked together on multiple different goals. While some were left with nothing to do because of the size of our class, they were being helpful as they documented the processes and took photos for those who were concentrated on their task at hand.
 I was with the group who did the parachute test and as you can see from the video, the payload picked up speed quickly and hit the ground with some force. I am worried that with the lengthy fall, from hopefully above the troposphere, the payload will reach a relatively high velocity and damage the camera as it hits the ground. If that happens hopefully we can recover the memory card and use that for viewing the video, otherwise it would be devastating if we couldn't.
 The mapping rig is created with a slight surprise, the camera just dangles from the balloon. I understand these plans have been refined and tested a handful of times, but it just seems like the camera will be swaying back and forth in the wind and possibly give us blurry pictures, or possibly some of the horizon and not the ground directly beneath. I wonder if there should be a weight to try and stabilize it as we walk around with the balloon 500 to 1000 ft above ground.

Conclusion:
 I am quite excited to be able to create a mosaic of our campus from a pocket camera. The images will hopefully have a high enough resolution that we can use it for other purposes in class. Our class did a great job of working together and splitting into groups to finish each task. In the class period we completed a mapping rig prototype and set up for the completion of the HABL rig. With all the weights and other testing done we should be ready any day to set our project into action. Later posts will have the results of each project.

Week 2: New and Improved Sandbox Exercise

Introduction:

 Last week was an introduction to the world of 3D modeling; we had the opportunity to go out and create our own terrain and find our own way of surveying the carefully crafted model. The group met, refined, and re-did the previous exercise. We used various interpolation methods to analyze the survey we completed and decided the best way to show what we created.

Methods:

 We started this activity by placing our original data into ArcMap. We did this by using the Add X, Y tool and imported the coordinate pairs and displayed it as a point based feature class. ArcMap is a handy software that provided us with many ways of representing our data by using interpolation methods. We entered our point feature class into 5 different 3D analyst tools; Inverse Distance Weighted (IDW), Natural Neighbors, Kriging, Spline and Triangular Irregular Network (TIN). (see Figures 2-1 through 2-4 on the Photos Page) These methods use our point feature class and form an estimated surface from the points using the z-values. They essentially use the points around each other to form a value, and when in 3D a slope, to satisfy the elevation variations of the points in the feature class. After creating all of these rasters it was possible to bring them into ArcScene and view them in 3D. The best interpolation method was chosen to represent our first survey of the terrain we created, Figure 2-4.

 After analyzing the models that were created it was plain to see there were not enough points collected to properly show all of the terrain's features. This brought an opportunity to go back out to the sandbox and create a new survey method to collect sufficient data to help display the created terrain. After reforming the terrain's features the group concluded on a larger resolution, 5x5 cm. We set up the grid similarily to our first exercise, but this time we stretched a string across the length of the sandbox at intervals of 5 cm. (see Figure 2-5) After pinning down the string across the sandbox we marked up the side walls every 5 cm and used those markings to lay a meter stick across the width of the sandbox. Using that meter stick we took measurements every 5 cm to come out with 22 measurements for each Y coordinate. (see Figure 2-6.) After the completion of our survey we had a total of 1056 points, quite the amount to type into a data table. Once the data was placed into a Microsoft Excel file we brought that table into ArcMap 10, and ran the Add X, Y tool once again, giving our data a spatial extent. The point shapefile was ready to use for running the 3D analyst tools once again.

Discussion:

 Our first survey got the designated job done, however it did not have nearly enough points gathered to give a proper visual representation of our terrain. After running the interpolations for our first survey it was interesting to see the results of each method. The method that best projected our terrain was Spline (see Figure 2-?); it gave our features the most realistic edges and projected the most properly. IDW gave very interesting results, the method works in such that it works as a function of inverse distance, the point measures out a distance and is influenced by certain points in the immediate vicinity. This gives the IDW method a circular look to each point location; (see Figure 2-4) this does not work well if you are looking for a realistic visual representation of the terrain that is surveyed. Though the 3D models worked very well for the points we collected we noticed some bad errors, we created a river in the southern part of the sandbox and as you can see from Figure 2-2 you can barely tell it is there. Also there is a ridge across the northern part of the map that was not meant to be located there, you can compare the photos of our terrain from Figure 1-6 and see there is no ridge in the northern part of the terrain. These errors would not have happened had we known to make smaller measurements; luckily this assignment allowed us to go back and recreate our terrain and make more accurate survey points.

 The second time around we decided to make measurements closer together as stated above, the results were significantly more accurate to what we created. Once the point feature class and the interpolations were done it was fascinating to compare the results. The maps do not look much alike, the new ones were significantly more accurate and when compared to the final product photos you can actually see what we created in our sandbox. Once again I chose the Spline method to represent our terrain as it worked very nicely to give shape to our features created as seen in Figure 2-7.

 If this lab was done again I would bring very fine string to create a full grid on the sandbox to help minimize the error of figuring the location of each measurement. Another adjustment would be to make sure all features do not break the top of the sandbox because it would help alleviate error once again by adjusting measurement methods by having to switch from measuring down and up from the string level. Otherwise the group was able to make the best adjustments for completion of the exercise the second time through.

Conclusion:

 This exercise was a great opportunity to produce a 3D rendition of a real life landscape, look at what you did wrong, and go back, refine, and redo the entire process. The chances to go back and clean up the errors you produced or adjust the surveying techniques you thought were good enough was critical for the success of what we had to accomplish. We didn't know what we were getting into the first time around and essentially 'winged it' so it was great to go back and do it the right way. The group performed very well together, we had no issues distributing the work load and discussing the best way to accomplish what needed to be done. I learned that there is always room for adjustment when doing something and that one way is never the best way of doing it. This activity would be best if it wasn't below freezing outside; otherwise I thought it was a great opportunity to form our own methods of completing the exercise.

Week 1: Sandbox Exercise

Introduction:
 The first week of Geospatial Field Methods consisted of a sandbox terrain exercise. The activity was to go out and construct an elevation surface of terrain using snow, as it is winter, and survey the created terrain with our own coordinate system. The exercise is to help us open our minds to geospatial thinking by crafting our own terrain and applying the surveying exercise to a real world experience or job. My group consisted of two other students and myself and we worked together to complete our task.

Methods:
 The first step was finding time to get together and do the project, we met on Friday (2/1/13) morning and went outside to our sandbox. The box was full of snow and that was the medium we chose to construct our landscape. There were a few land formations that were suggested to be included in our terrain such as a ridge, hill, depression, valley and plains. After construction of the terrain it was time to come up with our own coordinate system to help us complete a survey. Supplies were provided to make measurements and after concluding on our system we began to survey.
 Our coordinate system started with using the bottom left hand corner of the sandbox as our origin. We decided as a group to survey our terrain using 10x10cm squares. To do so we measured 10cm to the East and made a mark at each coordinate along the axis. Then we used a string drawn across the top of the sandbox as a locator for the position we moved north for each measurement. Our box was approx 100cm wide and 240cm long so we had about 240 points total. Our terrain was mostly below the top brim of the sandbox as there was about a 10cm difference from the basin to the top of the box. So to get the measurement of elevation for each coordinate we measured down from the string using a meter stick, as a result our elevation points were all below are beginning sea level. We later decided to alter our data and lower our sea level by 8cm so most of the terrain was above sea level.
 After gathering all our data it was necessary to put the points into a Microsoft Excel spreadsheet for further use in plotting those points in ArcMap 10.

Discussion:
 I felt our group did a good job of creating our coordinate system and finding an efficient way of completing the survey. We used two meter sticks, a few feet of string and a tape measure to finish the surveying of the terrain. The group was able to place each land form suggested into our sandbox, there was plenty of room to work with, maybe even too much space, luckily we needed some plains. (See Figures 1-1 through 1-6 on the Photos page). We made measurements as consistently as possible to avoid error or give all coordinate pairs the same error as each other. It was difficult to get the best survey because our coordinate grid was much to large for the delicacy of some of the landforms we created.
 Unfortunately our group neglected the forecast of the week and came Friday morning it was -7 degrees Fahrenheit outside. A High pressure system containing frigid Canadian air migrated south right over southwestern Minnesota on Thursday evening giving us those near frostbiting temperatures. Luckily we all came out unscathed from the cold after our task was done. (See Figure 1-7.)

Conclusion:
  This first exercise drew a good amount of attention from me, these skills attained from completing this assignment can be applied easily to what I aspire to do later in life. Surveying landscapes is always up to interpretation it seems and being able to go out and create our own method of doing so is a great challenge.
 I am very excited to see how the terrain turns out in ArcMap, the idea of going out and creating a simple land form outside and putting it into 3D modeling is a fascinating concept. I used to build and design landscapes and cities outside in my sandbox as a kid, who knew I would end up doing it as a student and possibly for the rest of my life. Programs such as ArcScene leave much for the imagination and inspire creation and innovation for many things.