Development of a Field Navigation Map

Introduction

     In this exercise we will be creating two different maps that will be used in navigating throughout the Priory in a future exercise. The Priory is located three miles south of the University of Wisconsin- Eau Claire along Interstate 94 on Priory Road (Figure 1). Formerly St. Bedes Monestary, the Priory was purchased by the UW-Eau Claire Foundation in 2011 and is currently being leased to the University of Wisconsin- Eau Claire for expaneded educational purposes. The Priory consists of 3 buildings totaling around 80,000 square feet of space on a 112 acre forested lot. The land is heavily wooded and contains a combination of flat terrain along with very steep ridges with a slope up to 63 degrees.

Figure 1  The Priory is found south of the city of Eau Claire, WI.

 

Methods

     An important part in navigating in the field is knowing your pace count. A pace is defined as the length of two strides by an individual. To determine pace count we set up a 100 meter stretch of sidewalk outside Phillips Hall, using a normal stride we counted how many times our right foot hit the ground throughout the 100 meters. My pace count is 67 paces per 100 meters, or 1.49 meters per pace. Knowing this information will provide a fairly accurate method for measuring distance traveled from one point to another in the field.

 

      The next step is determing what data to include on the maps. Although there was a lot of data provided in the Priory Geodatabase, I decided to gather data from outside sources. The first map I created (Figure 4

) contains the boundary of the Priory and a three inch aerial imagery provided by the City of Eau Claire. This map is projected with a UTM Zone 15 projection and contains a grid spaced at 50 meter intervals. The UTM coordinate system is a projected coordinate system that breaks the earth into 60 zones (Figure 2). The UTM coordinate system is designed to minimize distortion in the selected zone. In this case, the Priory is located within zone 15.

Figure 2  Universal Transverse Mercator (UTM) zones throughout the United States.

      The second map i created was a map showing the slope of the landscape throughout the Priory (Figure 5). Although there was a DEM available in the Priory Geodatabase, I found that the resolution was too coarse to calculate accurate slopes so I decided to use the much more accurate DEM created by the City of Eau Claire using LIDAR data. I then ran the Slope Tool, found in the Spatial Analyst Toolbox, to get an accurate map of the slope within the Priory. I used the same UTM Zone 15 projection as the aerial map to keep both maps as similar as possible. I then added a grid in decimal degrees which will aid in locating objects that have a geographic coordinate system, which is basically an angular measurement from the equator or prime meridean (Figure 3).

 

Figure 3  Illustration showing how decimal degrees are calculated.

                          

 

 

Results

      

Figure 4 Navigation map of the Priory using 3 inch aerial imagery and a projected UTM Zone 15 coordinate system.

Figure 5 Navigation map of the Priory using slope calculated from LIDAR data, provided by the City of Eau Claire,
using a decimal degree grid and a UTM Zone 15 projection.

Discussion

     I believe the two maps I created above will be sufficient for any future navigation exercise we partake in. I believe that less is more when in comes to map creation. Adding a bunch of different data to a map can cause it to become cluttered and difficult to read. With that said, I believe that only two different sets of data are needed to navigate through any terrain. The first set of data is a map with an aerial image. This map shows the overall landscape of the area. It provides information about vegetation and other physical features, such as rivers or buildings, that are present. The next piece of information that is necessary is slope. A map showing the slope of a landscape can be useful in determining the easiest way to navigate over a steep ridge or around a steep valley.
    
     I am a little worried that my maps will not print very well and will therefore be difficult to read while in the field. I feel as though adding more information to the maps, such as contour lines, would only increase the likelihood of the maps appearing too cluttered and messy. In reality, all a person should really need in navigating is the angle of the sun and a compass, so an aerial map and a slope map should be enough information to correctly navigate through the Priory.

Conclusion

      In conclusion, one must take into account several different factors when creating a navigation map. It is important to select a proper projection to eliminate major sources of distortion. It is important to have a detailed grid that will aid in keeping correct distance/direction. It is also important to keep the map uncluttered so it can easily be read while in the field. As previously stated, I have some experience using a compass and paces for navigating from my time in Boy Scouts so I look forward to seeing how much of that information I retained over the years.