In preparation of actual navigation at the Priory, navigation maps were created. This post walks through the making of these maps, one in decimal degrees, and one in UTM meters displayed in a certain way for easy use in navigation. This assignment helped build map making skills, and understanding of coordinate system grids and other elements of maps that can help navigation. Special care was taken at every turn to create a map that was easily interpreted on the ground.
The Priory lands are owned by the University of Wisconsin - Eau Claire and include converted housing and hilly woods. Figure 1 below shows the area in the larger context of Eau Claire. It is located about 10 minutes south of campus.
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| Figure 1 |
Methods and Discussion:
To begin, data that was supplied by the instructor (via a file geodatabase) and copied to a personal directory was brought into a new ArcMap document. This new ArcMap document was stored in this copied geodatabase. Sorting through the data information that was deemed necessary for the map was kept in the document and layers of data that was deemed unnecessary was removed from the map. The layers deemed necessary were the boundary layer, the "grdn45w092_13" raster which contained elevation data for the area and surrounding areas, and an aerial image.
The first step in mapping was to choose an appropriate projected coordinate system. For this the NAD 1983 UTM Zone 15N Transverse Mercator was chosen. This coordinate system uses meters, a key difference from some other projected coordinate systems because everywhere else in this project meters were used as well. One particularly important place where meters were used was in pace counting, in which we counted our personal amount of paces per 100 m. This pace count step was added in for low-tech navigation distance calculation in the field. This initial step dictated this spatial unit being used in the rest of the project. This projection displays the given area well with minimal distortion as it falls in the UTM vertical strip type Zone 15N.
Going forward, from the raster elevation data provided a 2 m contour line layer was created. 2 m was chosen for the interval parameter of the contour creation after careful comparison to 1 m and also 4 m were also chosen and decided against for sake of the contour lines being too far apart or too close together. The 2 m interval made sure that the lines were far enough to be differentiated, yet close enough to give appropriate detail. For this the Contour (Spatial Analyst) tool was used after turning on the spatial analyst extension under Customize, then Extensions.
After making this 2 m contour line layer, it needed to be clipped by the boundary of the priory area. For this the Clip (Analysis) tool was used, and careful attention to the help section popping up on the right side of the tool window to make sure the right layers were used in the right parameter input areas.
The project culminated in tweaking the display and symbology of all of these layers, as well as of the data frame, and inserting other layout view objects to make the map appropriate for use in the field. The layers were displayed in the following order (from bottom to top): base aerial image raster, contour lines, and finally on top of those the Priory boundary. The display settings of the base image were changed so that the image was 20% transparent. This ensured that the other features on top of it would be fully visible, yet vegetation detail that would give important context for location in the field would still be visible. Next, the contour lines were changed to yellow which made them visible on top of the darker background image. After going into the layout view and making sure the extent of the ground needed for navigation was visible in the frame, it was time to make a grid. This was created by going into the data frame properties, clicking grids, then creating two new grids (one for the meters, and one for decimal degrees). The meter grid was created as a "Measured Grid", and the decimal degree grid was created as a "Reference Grid" in the creation process. The settings selected for these two different grids are shown below in Figures 2-3. The resulting grids were added one at a time to the map using the check boxes next to the grids, then used to create each map before each was exported as a PDF file.
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| Figure 2 |
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| Figure 3 |
The next step was inserting all of the other miscellaneous items that made the map functional in the field. A north arrow was inserted. A scale bar was inserted and changed to meters to keep the units consistent across the map. A scale text was also inserted. Other proper information added were the contour interval, a title, a watermark with name, a personal pace count, projection information, data credited to the instructor, and a legend that showed that the black boundary line was the boundary of the Priory land.
Results:
The process, careful to consider as many needs of the navigator on the ground as possible, resulted in the following maps (Figures 4-5)
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| Figure 4 |
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| Figure 5 |
All data provided by Dr. Joseph Hupy
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