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Saturday, May 11, 2013

ArcPad Data Collection


Introduction:

For this week’s activity, my class and I went about setting up a data collection procedure by creating a geodatabase with feature classes and deploying them to a Trimble Juno GPS unit to collect data at the Priory in Eau Claire (Figure 1). The main purpose of this activity was to create a database for the Priory with information on the area for recreational purposes and to help restore it in the future. We were able to work in groups and choose one or two features that we wished to map. Then we had to plan the fields and domains that would accompany the features we would include for our portion of the map. There were several options to select from including trails, view points, erosion points, trees—dead or notable—or various man-made objects. My group and I decided to focus on the man-made objects by mapping any signs or garbage that we found in the Priory.


Figure 1: This is the Trimble Juno unit we used to collect data in the field.
Study Area:

The area we have been working in is known as the Priory and is owned by the University of Wisconsin-Eau Claire. It is located on the south side of the city of Eau Claire in Wisconsin in a more rural setting. The Priory is a hilly area with several steep ridges and gorges and is mostly wooded. There are some open areas near the Priory building, a house, and a waste pond located on the site, however (Figure 2).

 



Figure 2: This is an aerial image of the Priory in Eau Claire, Wisconsin. The outline defines our navigation boundary. As can be seen, most of the area is covered in trees.

Methods:

Once we had chosen the two features that we wished to map, my group and I had to come up with the fields and domains that each feature would include. For the garbage, we decided to create three attributes—material, size, and type of garbage. Then, we came up with several options for each attribute and made domains from these. The domain type that was appropriate for this situation was a coded value domain. The coded value domain allows the user to specify specific options for the attribute that will later be selected from a drop down menu. Once the values are set in the domain, the user cannot choose any other value. For example, for the garbage material attribute, we created four values that could be potential material types—plastic, paper, aluminum/metal, and other. Then we set up the coded value domain to text and entered in these options. Later, in the field, we could only select one of those four material types.  The advantage of setting up the domain in this way is that there is less user error through misspelling and it is faster/easier to enter in the values while in the field. The rest of the attributes and domains for the garbage and signs can be seen in the following table. Every domain was set to be a coded value text domain. All of this work can be done within ArcCatalog and ArcMap and should be saved to a geodatabase.
Figure 3: This is a table that includes the features and their attributes and domains. We used these to collect the features in the field and describe them by their attributes.


After the data had been set up in Arc, we had to deploy our features to a Trimble Juno GPS unit. Before doing so, however, we had to change the symbology of our features so that they could be easily recognized in the field. We also had to ensure that the fields and domains were set correctly. We used the ArcPad Data Manager Extension and toolbar to do this. Basically, we converted the map we created in ArcMap (.mxd file) to an ArcPad map (.apm file). ArcPad is simply software designed for mapping purposes on a mobile device. From that point, we just copied and pasted the .apm file into the SD card of the Juno GPS unit which we could pull up on the unit in ArcPad.

With the geodatabase and  data deployed to our units, we were ready to collect the data in the field. This was a relatively intuitive process. We brought up our maps on our respective GPS units and then selected the appropriate feature we were mapping as we stood near it. Once selected, we had to fill in the fields we created earlier with the values generated within our domains. My group and I also decided to pick up the garbage we were mapping along the way to help clean up the Priory as well. After collecting the data, we uploaded our points back into ArcMap and were able to view the results.

Results/Discussion:

Although we were unable to collect data throughout the entire Priory, we found some patterns with our data. Most of the garbage we found was near the parking lot area and along the tree line going into the forest. Once we were in the forest, however, we found little to no garbage. As for the signs, we found two distinct areas/types for the most part. The first was a group of parking signs surrounding the parking lot. The second was a group of signs that delineated a trail through the woods. Other than these, there were few signs to be found.
Figure 4: This is a map displaying the locations of garbage and the garbage material. Most of the garbage we found was plastic.
 
 
 Figure 5: This map shows the garbage size. Most of the garbage we found were small items. We had one point that was actually a large group of garbage that we labled "other".


 

Figure 6: This map shows the garbage type by location. We found a wide variety of garbage around the area, so most of the garbage types are classified as "other".

Figure 7: This is a map displaying the locations of garbage for each group member. As can be seen, most of the garbage we found was near the side of the building in the center. This is likely due to the fact that there were two dumpsters near that spot, and the garbage flew out of the dumpster onto the ground.

Figure 8: This is a map of the signs we located represented by their color. Most of the signs were an orange color because they were trail markers along one of the trails in the Priory.

Figure 9: This is a map of sign material. A vast majority of the signs were made of metal, though we found one that was made of wood.
 
Figure 10: This is a map displaying the location of different types of signs. We had a pretty even split between navigational signs and informational signs. The navigation signs were trail markers and the informational were parking signs along the large parking lot near the building in the center.

Figure 11: This is a map of the signs collected by each group member. As can be seen, most of the signs followed a path along the northern part of the image and another large group surrounded the parking lot in the southwester part of the map.

This project, though seemingly simple, turned out to be a bit difficult for the class. My group and I had little trouble using the GPS units to collect our data, but other groups struggled with technical problems with their GPS units and setting up their domains. The only issue my group and I had was that we did not have the exact same fields for our data. One member decided to omit the “Shape” field for our signs while another did include it. We also forgot to include a notes field for the garbage feature, so we could not write any additional information on those points. In the grand scheme of things, this was a minor issue. We also were unable to walk throughout the entire Priory, so our data is limited to the southwestern section of the area.

Conclusion:

Overall, this project helped the class learn how to set up data for data collection from the ground up. We created our own geodatabases and came up with features with unique attributes and domains. This is an extremely valuable and powerful skill and will likely be used in the future. The project also helped us to understand more about domains, how they work, and why they are useful. Then, we used this data to collect the locations of signs and garbage out in the Priory. My group and I were fortunate enough to run into very few issues with our data, though we were unable to completely survey the area we were working in.

High Altitude Balloon Launch (HABL)


Introduction:

As our last balloon launch, my class and I sent an eight foot diameter balloon along with a camera and rig up into the stratosphere to collect images. We have been leading up to this launch for quite some time as we developed the rigs months ago and have been testing out the balloons for our aerial imagery projects. We weren’t sure what to expect in terms of distance or the imagery we collected, but were very happy with the results. The balloon reached a height of about 100,000 feet above the Earth’s surface and travelled nearly 80 miles over the course of about an hour. The balloon eventually popped due to pressure in the atmosphere and fell near Marshfield, Wisconsin. We were then able to find and gather the balloon and view our imagery. We were able to collect some really fantastic imagery of the Eau Claire area and western Wisconsin.

Figure 1: This is the path that the balloon flew after it was released from the UW-Eau Claire campus. (Map credit to Joe Hupy.)
Methods:

The rig for this launch was created back in February along with the rigs for the aerial imagery balloon launches. We used a Styrofoam bait warmer to hold the camera with heating packs inside to keep the camera from freezing at such great heights. We also cut a hole in the bottom of the bait warmer to fit the size of the camera lens so that it could collect imagery of the Earth. Four strings about three feet long were tied to the warmer and taped along the sides connecting at the top with a carabiner at the top to suspend the rig from the bottom of the balloon. A GPS unit was also attached so we could track the balloon and collect it once it landed. A parachute was attached so the rig could land safely after the balloon popped up in the atmosphere as well. The camera we selected for the HABL was a digital flip camera, and we took video rather than a continuous shot mode as we had for the aerial mapping launch.


Figure 2: This is a photo of the rig that we created for the high altitude balloon launch. It was developed earlier on in the semester.


On the day of the launch, we filled the balloon using a large helium tank. We had to be sure to fill the balloon with enough helium that it would rise quickly, but also leave enough space for the helium to expand with the higher altitude without popping the balloon right away. Once the balloon was filled properly, we attached the rig, making sure the camera was set to the correct settings. Then we were ready to launch the balloon. We chose to release the balloon at 10a.m. on the 26th of April because the weather conditions were most permissible at that time. The balloon was let go in the center of our campus mall.
 Figure 3: This is an image of the class walking the balloon to the center of campus for the launch after it had been filled.
At first, we weren’t receiving a signal from the GPS unit attached to the rig and weren’t sure if we would be able to recover the footage. Fortunately, after about an hour, the signal appeared near the city of Marshfield, Wisconsin—78 miles east of Eau Claire. Our professor and a couple students then set out to find the balloon and bring back the rig. They found that the balloon had landed on some private property and had to ask the land owner’s permission to retrieve the rig. They received permission and ended up having to climb up a 50 foot tree to get it down. Our professor had to saw off a limb of the tree to actually recover the rig.
 Figure 4: This is an image of our professor climbing  a 50 foot tall tree to retrieve the HABL rig. He ended up sawing off a large branch of the tree.

Results/Discussion:

The HABL was an overall success—we were able to recover some amazing images from the camera and have a video of most of the flight. There were several aspects of the rig and camera that did not go perfectly, however. Unfortunately, once the camera had reached a certain height, condensation began to cover the camera lens producing a hazy film for some of the imagery. The camera was only able to capture about an hour of footage before the battery died, as well. This wasn’t a huge issue as we were still able to see the launch up through the point where the balloon began its descent, but it would have been nice to see the entirety of the launch. We also decided that any future launches would also include a barometer, thermometer, and anemometer to collect more information about the flight.

Figure 5: This is a stillframe from the balloon as it left the UW-Eau Claire campus. This is one of the very first images that was collected during the flight.

Figure 6: This is an image of the Chippewa River to the east of Eau Claire. As can be seen, the balloon had reached much greater heights at this point than it had while it was near the campus.

Figure 7: This is one of the last images taken by the camera before the battery died at about 100,000 feet in the air.

Conclusion:

The high altitude balloon launch was an amazing experience for our class. Very few people have been lucky enough to send a balloon up into the stratosphere at 100,000 feet above the surface of the Earth and collect imagery themselves. Although there were a few issues with the HABL, our hard work and planning for the rig paid off. Below is a link to a video that our professor created to summarize the launch.