GIS 1 LAB 3: INTRODUCTION TO GPS

Introduction:

Global Positioning Systems (GPS) is a very powerful tool with many capabilities. However, without being familiar with the devices and tools used to collect data, it will be nothing but an hindrance. In order to avoid this happening in the future this lab assignment's goal is to walk through all of the steps necessary to carry out data collection using GPS software, tools, and devices from pre-data collection all the way to a final product (a map).

The following objectives outline this start-to-finish process:

1.       Create a geodatabase.

2.       Prepare the geodatabase for deployment to the Trimble Juno for field data collection using ArcPad Data Manager.

3.       Load the Geodatabase onto the Trimble Juno.

4.       Become familiar with the basics of the Trimble Juno GPS and ArcPad through an instructor-

       led demonstration.

5.       Collect point, line, and polygon features in the field using ArcPad on the Trimble Juno GPS

6.       Check the collected data back into ArcGIS from the field.

7.    Create a map displaying the collected data.

Methods:

Each of these objectives required different tools and operations for successful completion.

Objective 1: Creating a geodatabase

ArcCatalog was used to build a geodatabase. A geodatabase must be carefully prepared before entering the field to ensure a smooth data collection process. Details to be considered include establishing a coordinate system, creating appropriate feature classes, choosing the correct shapes (points, lines, or polygons), and determining the fields you will want in order to help you recall details about data being collected.

For the purposes of this exercise 3 practice and 3 regular feature classes were built, two each of points, lines, and polygons. An additional feature class, already built, was added containing polygons for the different buildings on campus. Next, a raster dataset with the outlay of the University of Wisconsin - Eau Claire campus was imported. This would allow the user to get a better sense of whether or not the features were being correctly added based on where the campus buildings were located on the map.

All of these feature classes were then added to a new map in ArcMap. Before moving on from this objective, it was important to alter the symbology of the feature classes rather than leave the default colors chosen in ArcMap. This is done to ensure the colors chosen will be easily identifiable as data is being collected.

Objective 2: Preparing geodatabase for deployment

Within ArcMap, the ArcPad Data Manager tool was used to "check-out" all the geodatabase layers and "copy-out" all other layers including the base map in the Action Menu. This essentially created a folder that would be transferred to a GPS unit

This folder was given a unique name associated with the project. It may be that a GPS unit has other folders already loaded onto it. Selecting a specific title ensures you will be able to locate the correct folder for your project when you are in the field.

 All of this creates "ArcPad data," which is effectively deployed when you finish this process.

Objective 3: Load geodatabase onto GPS unit

The GPS unit used for this project is the Trimble Juno 3B. A USB cable was connected between the computer and this GPS unit. The folder prepared (as explained in Objective 2) was cut out of its current location and pasted into the appropriate folder on the storage card of the Juno GPS unit.

It was also necessary to ensure the transfer was successful. The Trimble Juno 3B was turned on and the map that had been deployed was located indicating the transfer had taken place successfully. Within the Table of Contents under Layers, it was also verified that all of the layers we expected to be there, were indeed there.

Objective 4: Become Familiar with the Trimble Juno 3B

Utilizing the practice point, line, and polygon feature classes we developed, data was gathered using ArcPad on the Trimble Juno 3B to become familiar with the process before actually locating the data for the rest of the lab assignment.

Objective 5: Collect Point, Line and Polygon Features using ArcPad on the Trimble Juno 3B

After waiting for a "fix" assuring the unit was in communication with satellites, 4 specified areas (polygons), a footbridge (line), and three trees and lightpoles (points) were collected using ArcPad on the Trimble Juno 3B by selecting Add GPS Vertex. As features were collected information was entered into a Type field to help categorize the features.

Objective 6: Check collected data back into ArcGIS

After all the data was collected, the GPS unit was reconnected to the computer with a USB cable. Using Windows Explorer the folder containing the data was cut from the Juno 3B and pasted back into my personal folder. The ArcPad data manager toolbar was used to "check in" all of the feature classes from the Juno 3B. This made the collected data visible in ArcMap.

Objective 7: Build a Map with collected data

ArcGIS  was then used to build a map containing all of the necessary elements and displaying the collected data. An updated basemap was added providing a better reflection of the current campus layout.

Within the properties of the feature classes, the different polygons and points were differentiated from each other under the Symbology tab. This way, when the legend was built light poles were signified differently than trees, etc.

Results:

Figure 1: This map shows the features collected per the direction of the assignment

 

 

The map produced (as seen in Figure 1) leaves something to be desired in my opinion. Many of the features at the bottom-right of the map are bunched together, and some even overlap. Clearly, this particular GPS unit does not contain the necessary point accuracy to produce features sufficient for mapping. In addition, the blue "circle" is not in any way shaped properly. While many points were taken to ensure accuracy, the GPS unit is just not capable of the precision required to build a feature that better represents what is actually there. One of the lawn portions, especially, falls short of the actuall lawn. Here again, the GPS unit, was just not able to precisely locate the data being collected.

 

Due to the spread out nature of the data (with the bridge being so far away from the other points), this map appears very empty. and does not contain good balance.

When looking at my points, I had taken the point of one tree twice. I had to delete this data point for accuracy. Also, the line for the bridge was hard to replicate. I probably should have made the line thicker and just covered the entire bridge for the sake of being aesthetically pleasing.

Sources:

Data Source: GPS data collected by Nathan Schaffer
Aerial Map: ArcGIS Online, UWECCampusBaseMap
Topographic Base Map: UWEC Server, W:\geog\LidarData\EauClaireCity_3in_2013\MrSids folder