Using ArcPad to Collect Field Data

Introduction

The final exercise of the semester involves collecting data using a mobile device. In this particular instance, a Trimble Juno GPS will be used in conjunction with ArcPad to collect field data at the Priory. We have spent a good amount of time this semester out at the Priory, which is a plot of land recently purchased by the University of Wisconsin - Eau Claire, which is now a daycare center. Other than the daycare center, the rest of the property is occupied by forest with ever changing topography. There are some trails evident but have not been properly kept up and the trails are poorly marked in spots.

Fig. 1 - Trimble Juno GPS used to collect the field data.

The goal of this assignment was to collect certain types of features at the Priory so that the data could be compiled into useful maps. Being able to understand and employ ArcPad in the field is a crucial asset as this has become a very popular way for companies to collect data in the field. After the data collection is complete, the data will be uploaded into ArcGIS where feature classes will be created and then overlaid on top of a high resolution aerial image.


Study Area

Fig. 2 - The Priory is approximately a 4 mile drive from the University of Wisconsin - Eau Claire campus.



Fig. 3 - Aerial photo of the Priory - Eau Claire, WI.

The total land area that this exercise will take place on is approximately 112 acres in size and consists of hilly and woody terrain.


Methodology

In order to efficiently complete the field work in a 3 hour time period, the class split up into 6 groups.

Fig. 4 - Groups and their respective members. 

 Some of the features that were assigned to different groups were: Trails (type, condition), Trail Markers (color, shape), Benches (condition, azimuth), Erosion Points, Fallen Trees (lying over trails), Animal Tracks, Birdhouses, and Garbage (piles of garbage or abandoned equipment). After each group knew what they would be mapping, we needed to setup a geodatabase in ArcMap. The geodatabase was named appropriately and assigned the coordinate system NAD_1983_HARN_Wisconsin_TM. Once the preliminary steps of creating the geodatabase was complete, we added two point feature classes to it: Benches and Markers. Since each feature class had different criteria possibilities, it was necessary to create fields and domains for each feature. For Benches, this meant including an Azimuth field ranging from 0-365, and a Condition field with options Good, Fair, and Poor to describe the bench's condition. For Markers, a field was created for Shape (no domain was set for this), Medium (wood, metal, or other), and Color (no domain was set for this either). The fields where no domain was set is because we were not sure how many different colors were used for trail markers or how many different shapes there were. Because of this, we did not want to limit our options by creating a domain. However, we could still be able to manually type in the text values on ArcPad in the field. The benefit of using domains is that defined values can be used to mitigate manual entry error.

After we had defined all of the conditions, it was time to export the geodatabase onto a Juno GPS unit. This can be done through the ArcPad Data Manager Toolbar.

Fig. 5 - The ArcPad Data Manager toolbar in ArcMap 10.1.

By clicking on the Get Data button, circled in red, the wizard takes you through the steps for getting the data ready for ArcPad. This involves defining the folder path to where the data will be stored. An ArcPad map project will be made with a .apm file extension. After this, the data will be deployed to the appropriate folder. The next step is to connect the Juno to the computer via USB cable. The deployment folder can then be pasted onto the SD card inside the Juno. It is best to check the Juno to make sure the process was completed properly before heading out to the field. So no we have the geodatabase containing the feature classes on the Juno as well as an aerial basemap which will run in the background. The basemap is optional as it is useful but can bog down the system.

Once we arrived at the Priory, all we needed to do was wait for a GPS signal lock and then we took to the woods to start collecting data. After a half hour of data collection, it was evident that with all of the trail markers on the trees, it would take more than our allotted class period to collect all of the data. We split the group up so that I would collect all of the triangle shaped trail markers, Kent would collect the circle shaped markers, and Beatriz would collect the benches. This proved to be a way more efficient way of collecting the data and we had it all collected within 2 hours. Once, the data collection was complete, we headed back to the computer lab to upload the data into ArcMap. A tool called Bearing Distance to Line was run on the Benches feature class in order to show the azimuth of the view from each bench. We did not collect data on the view distance from each bench so a standard 25m distance was given to each bench. The important thing here is that we can see which way the bench is positioned.

The data was saved on the Juno as an .ssf file which is not directly supported in ArcMap. In order to convert this to a shapefile, we had to employ the ArcPad Data Manager once again. This time, we clicked on the Add Data icon and uploaded the .ssf file. From there, it recognized our Benches and Markers features. We clicked both of them and then clicked the "Check in" button which updated our reference geodatabase with the new attribute data for our features.

Fig. 6 - Updating the geodatabase with feature point data collected with ArcPad.

Results/Discussion

Fig. 7 - Trail markers and benches at the Priory.

Fig. 8 - Zoomed in look at the trail markers and benches.

The first time employing an ArcPad project into the field was very successful. There were a few groups who lost their data in transition from the field to computer. We were lucky enough to retain all of our data. We were able to gather all of the data we originally set out to in the allotted time. We ended up with 51 trianle markers, 51 circle markers, and 6 benches. It looks like the benches are spread around the trails in a very even manner. It is a bit confusing determining what the triangle and circle markers differentiate. We only saw one sign indicating a trail name. Also, it was quite common to see a triangle marker on one side of the tree and a circle marker on the other side. Perhaps the different shapes indicate the direction of travel on the trail. Now that they are mapped, the coordinator at the Priory can clear up this confusion. We also entered attribute data for the condition of the markers as well indicating if they are clearly visible, need paint, or if they are on a fallen tree of which a few were.

Conclusion

This exercise was beneficial in two ways. First of all, we got invaluable experience with another component of ESRI software in ArcPad. This sort of skill is highly marketable as this is a very popular method in data collection. Secondly, the types of data and the detail it was collected in, both spatially and attribute, will help the coordinator at the Priory with improving the trail conditions. Maps containing multiple datasets can be made to allow visitors to navigate with ease and allow them to have an enjoyable time exploring the woods at the Priory.