Developing a Field Navigational Map
Introduction:
The objective of this lab was to construct a set of navigational maps that are to be used in a future navigation activity. Navigation requires several things. First, the navigator must be able to orient his/her self. Second, there must be a projection of some kind so that they can reference their position. In the case of our navigation activity we will be using our navigation maps and a compass to traverse a course on the grounds of the UW-Eau Claire Priory.
Methods:
Proper navigation requires the navigator to know their direction and distance they have traveled. For the future navigation exercise a pace count will be implemented to determine distance traveled. The pace count involved the measuring our of a 100 meter stretch. The walker (myself) then walked the 100 meters twice and took the average amount of steps it took to travel 100 meters. To create the navigation map a database containing aerial imagery and 2 foot contour lines of the area of interest (Priory) was provided to us.
The map coordinate system and projection are the essential components of any map. In the case of this navigational map the coordinate system used was the Nad83 datum. The Nad83 or North American Datum 1983 coordinate system was implemented to replace the aging Nad27 datum. The Nad83 coordinate system defines a geodetic network in North America and is commonly used throughout North America. In the case of map projection the map projection used for this navigational map was the UTM (universal transverse Mercator) projection. The UTM system divides the Earth into 60 zones. Each zone is six degrees in longitude and distortion is minimized in each zone. The Priory is located in UTM zone 15 so that is the zone that was selected to minimize distortion.
After the map coordinate system and projection was set a grid was placed over the top of the map. Two separate maps were generated utilizing two different types of grids. The two types of grids that were used included the graticular and UTM grids. The graticular grid utilizes latitude and longitude points while the UTM grid simply uses easting and northing coordinates. After the grids were selected and created the last step involved removing some of the contour lines. The map was very cluttered so every third contour line was removed. Below is the selection that was used to select for every third contour line (Figure 2).
The objective of this lab was to construct a set of navigational maps that are to be used in a future navigation activity. Navigation requires several things. First, the navigator must be able to orient his/her self. Second, there must be a projection of some kind so that they can reference their position. In the case of our navigation activity we will be using our navigation maps and a compass to traverse a course on the grounds of the UW-Eau Claire Priory.
Figure 1. Above is the area of interest outlined in red. The Priory is labeled in white.
Methods:
Proper navigation requires the navigator to know their direction and distance they have traveled. For the future navigation exercise a pace count will be implemented to determine distance traveled. The pace count involved the measuring our of a 100 meter stretch. The walker (myself) then walked the 100 meters twice and took the average amount of steps it took to travel 100 meters. To create the navigation map a database containing aerial imagery and 2 foot contour lines of the area of interest (Priory) was provided to us.
The map coordinate system and projection are the essential components of any map. In the case of this navigational map the coordinate system used was the Nad83 datum. The Nad83 or North American Datum 1983 coordinate system was implemented to replace the aging Nad27 datum. The Nad83 coordinate system defines a geodetic network in North America and is commonly used throughout North America. In the case of map projection the map projection used for this navigational map was the UTM (universal transverse Mercator) projection. The UTM system divides the Earth into 60 zones. Each zone is six degrees in longitude and distortion is minimized in each zone. The Priory is located in UTM zone 15 so that is the zone that was selected to minimize distortion.
After the map coordinate system and projection was set a grid was placed over the top of the map. Two separate maps were generated utilizing two different types of grids. The two types of grids that were used included the graticular and UTM grids. The graticular grid utilizes latitude and longitude points while the UTM grid simply uses easting and northing coordinates. After the grids were selected and created the last step involved removing some of the contour lines. The map was very cluttered so every third contour line was removed. Below is the selection that was used to select for every third contour line (Figure 2).
Figure 2. The select by attributes function was used to select for every third contour line. The function to select for every third contour line is shown above.
Results:
The final maps are displayed with the grids imposed over the top of them for reference during navigation (Figure 3, Figure 4). Each grid square represents 0 degrees, 0 minutes, and 1 second in figure three. While each grid square represents 50 meters in figure four. Although the clutter from the contour lines was reduced by removing every third contour line. There is still clutter from the contour lines in areas where there is severe elevation change. This can be seen in the west central portion of the maps.
Figure 3. The graticular style grid laid over-top of the Priory map. The contour lines are shown in blue. Key map information such as the north arrow, step count, coordinate system, projection, map scale, and data source is located on the right side of the map.
Figure 4. The UTM style grid laid over-top of the Priory map. The contour lines are shown in blue. Key map information such as the north arrow, step count, coordinate system, projection, map scale, and data source is located on the right side of the map.
Conclusion:
This activity proved to be useful in developing the skills associated with proper navigational map construction. Map coordinate systems and projections are critical in the creation of a useful navigation map. This activity certainly reinforced this reality. Although the information on the maps appear small, when printed out on a 11 inch by 17 inch surface the maps should prove to be very informative and useful.
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