Field Navigation III

INTRODUCTION
This week, we expanded on the navigation exercises of the previous weeks.  A GPS unit was used to navigate to waypoints without the use of a map or compass.  Students were provided a list of Lat/Long points by the professor for each waypoint.  Students activated the tracklog feature of the GPS unit in order to track their route throughout the activity.

METHODS
To begin this activity, we had to find the starting point of our route, the location was indicated by the list of lat/long points given to us by our professor.  Our groups starting point was near the gazebo at the Priory.  At the starting point, we activated the tracklogs on the GPS units.  We made sure to activate only when we reached the starting point so only our course was tracked.  From the starting point, we used the lat/long feature of the GPS unit to navigate to the first way point (Figure 1).  We observed the increase and decrease of the lat/longs on the GPS unit to determine which direction to travel.  If we needed to go north, we would watch for the latitude number to increase; decrease for south.  To travel east we watched for the longitude number to increase; decrease to travel west.  This was done for all six waypoints on our course (Figures 2 & 3).  After we had found each waypoint, we traveled back to the starting point to complete the course.  Upon reaching this point, we turned off the tracklog.

Figure 1-Navigating with the GPS unit

Figure 2- Zac & Phil at the second waypoint

Figure 3- A waypoint in our course

Using the DNR Garmin application, students uploaded their individual tracklogs onto a computer.  Through this program, the tracklog could be easily converted into a point shapefile.  The shapefile was then imported into the class geodatabase.

Three maps were created for this activity; Class tracklogs (Figure 4), Group tracklogs (Figure 5) and individual tracklogs (Figure 6).

Figure 4- Map of the tracklogs for each student in the class

Figure 5- Map of my group's tracklogs

Figure 6- Map of my individual tracklog

DISCUSSION
Technology does not always make navigating easier.  Although we were allowed to use a GPS unit to navigate this week, it was not easier than the compass and map navigation.  It was somewhat difficult to determine the direction of travel using lat/long the the GPS and a group member had to be constantly watching the lat/long numbers to make sure we didn't stray off of our direction.  It was more difficult in my mind to navigate this week compared to last week, but it took our group less time to navigate using this weeks technique.

It is noticeable that the tracklog does not fit exactly with the waypoints.  This is because of the accuracy of a GPS unit and the tranformations from the GPS unit to a GIS shapefile.  This also skewed the starting and ending points of the course.  Even though our group walked to the starting points after the course was completed, the route is not "closed" according the the maps.

CONCLUSION

There are many techniques that can be used for navigation.  A map, compass or GPS unit are just a few of these techniques.  It is good to know how to use each of these individually as well as together.  A combination of these three techniques would allow for the must efficient and timely way to navigate.  GPS units are very accurate, but one must always observe the changes that may occur when transforming the data from GPS to a computer (GIS).  This can be avoided in some ways through a similar spatial reference for the GPS and the GIS.  If the data is still skewed, it can be manually edited in a GIS.