Lab 6: Navigation with Map and Compass

Intro

The task for the second half of our land navigation lab is to first plot the UTM coordinates of our way points on the map, and then to successfully navigate the course using nothing but a compass to plot azimuth and the scale included on our map to determine distance between the points.

Methods
To successfully navigate the course, preparing our materials was crucial due to the amount of cumulative error that could be encountered when navigating from point to point using such basic instruments.

Step 1: Point Plotting

            With our maps in had that we created in the previous weeks lab, our first task was to plot all six of our way points using nothing but the UTM coordinates. Point plotting was fairly strait forward because of our well labeled axis, and with relative ease. To help mitigate error, each team member plotted their points individually and then collectively compared them to create the final map that would be used when calculating azimuth and distance. Lines were next drawn from point to point, one through six, to serve as visual aids when determining azimuth.



Fig. 1: The way point coordinates for land navigation of the Priory were presented to us on an Excel spreadsheet. Our group was on course three and plotted the bottom six points using the their UTM coordinates.

Fig. 2: Shown here is myself and another team member plotting the UTM coordinates of our way points prior to heading out into the field.

Step 2: Calculating Azimuth & Distance

Fig. 3: Shown above is a reference image of the type of compass we used to both determine the azimuth from point to point and also to navigate the Priory.

            We used a basic field land navigation compass to determine azimuth by centering the north oriented compass over point one. Azimuth to the next point was then determined by recording the degree value where the line to the next point was intercepted on the compass bezel. We recoded each azimuth value from point to point on a chart that would later be used to set our compass to when in the field.

Fig. 4: Using a basic field navigation compass and the methods listed above, we calculated azimuth from point to point that would later be used when navigating the Priory to find our six way points. 

           Distance from point to point was determined by using the scale (meters) we included on our final map and then compared to our hundred meter pace count to determine the amount of paces needed to travel from point to point.

Step 3: Establishing Azimuth in the Field from Point to Point 

            Holding the compass close to your chest and away from any metal objects that could cause error and pull the compass needle away from true north, the first azimuth value is dialed in to line up with the heading arrow. By placing the needle inside of the red north arrow inside of the compass your bearing is set and you simply head out in the direction that the heading arrow is pointing. Using landmark objects that line up with the heading arrow you simply pace off to that landmark, re shoot azimuth to a new landmark and continue to do that with the set bearing until you reach your way point and then start the whole process over.

Fig. 5: Shown here, using the methods listed above, is a team member pacing out to a predetermined landmark that was in line with the correct azimuth to the next way point.

Fig. 6: Shown here is a team member stopping to make sure that our line of travel stayed on the correct bearing to the next way point. This image is taken from the point of view of the team member who was in charge of directing the walker to stay on course with the correct bearing. 

Fig. 7: Shown here is our team at the first way point we found when navigating the Priory using only a compass and pace count.

Discussion

            Due to the relatively short distances (<400m) from point to point on the land navigation course, any error in our azimuth or distance values was not magnified too much because our calculations put us within the general location of the blaze orange colored way points that contrasted the white snow very well. For all of the way points, we usually had a visual conformation of them within 50 meters of actually reaching them.

            Aside from using the map  to plot and calculate azimuth and distance between points, our group hardly used it at all when traversing from point to point out in the field because of the reference table we created containing the azimuth and distance values before heading out into the field. To check the accuracy of the contour lines though, we did locate ourselves on the edge of a steep ridge to see how well the map depicted the physical topography of the Priory landscape, and it did.

Conclusion

            Our team found all of the way points on our course (#3) within the allotted time given, and did not get lost in the process. I accredit this success to the preparation of our reference map, and also the amount of time we spent collaborating when plotting our points to put them in the most accurate location. The amount of preparation we spent on this lab directly fed into its success, and just goes to show how important it is to prepare and double check all parts of the task prior to heading out into the field.