Field Activity #4: Development of a Field Navigation Map

Introduction

This lab consisted of creating two maps that would be used to navigate the Priory in Eau Claire, WI in a future Field Activity. The Priory in Eau Claire, WI is located at 44°45′55.6″N 91°30′41.4″W, Figure 1. Shows were the Priory is located. The goal of this lab was to familiarize oneself with coordinate systems and map projections when creating navigation maps. A coordinate system uses 3-D modal compared to a map projection that uses a 2-D modal. In a sense then a coordinate system is always geographic so it is usually referred to as geographic coordinate system (GCS). A map projection used the GCS to project a 2-D view of the globe. The two maps created needed to have GCS and map projections that would be logical to use in navigation. The criteria for the maps were that one had contain a UTM  (Universal Transverse Mercator System) grid with fifty meter spacing and the other one had to use Geographic Coordinates (GC) in Decimal Degrees (DD). For this Field Activity we were given access to a Geodatabase (GDB) by Professor Hupy that contained all the data we would needed to complete our maps. 

Figure 1. Satellite Image View of Priory in Eau Claire, WI

Methods

Since we will be using these navigation maps later on in a Field Activity we counted out a pace of 70 per 100 meters, using a measuring stick (Field Activity #2, Figure 2). This is the number of steps that an individual takes in 100 meters. This can be referenced whenever using a navigation map. The first step in creating these navigation maps was to look at the data provided and decide what to use and how to portray the area. Within the GDB that was provided three LiDAR rasters, shapefile of the boundary of the Priory, and Eau_Claire_West_SE basemap of the area were used. Most of the data within the GDB didn't have any GCS or map projections associated with them, so the define the projection tool was used. This tool is found under Data Management Tools --> Projections and Transformations--> Define Projection. The projection was set to Transverse Mercator. This was the projection of the Boundary layer for the Priory so it was used as the projection. Also, the GC was set to NAD_1983_UTM_Zone_15N.  Using these GC and projection specifies distance conservation and area of the location that is being mapped. Since Eau Claire, WI was in the UTM 15 zone, shown in Figure 2. This was chosen to best depict the area of study.

Figure 2. UTM Zones in the United States of America

When creating a navigation map one doesn't want to overcrowd it with adding too much data. The GDB provided a shapefile of 2ft contours. Since we are using metric units of meters this had to be converted to meter contours. When trying to convert a spatial reference error came up. To overcome this a different method of creating meter contours was taken. A mosaic dataset was created to combine all of the LiDAR rasters. This way they could all be edited as one raster. Then the contour tool was used. This can be found in Spatial Analyst Tools--> Surface--> Contour. The parameters set for this tool were contour intervals of 3. Also, because the data was created in feet it had to be converted to meters. This was simply done by adding 0.3048 as the Z factor. The Z factor is by default one representing 1ft., so by putting in 0.3048 it converts it to meters, shown in Figure 3. The mosaic dataset was used again. This time the tool hillshade was used. This tool is located in Spatial Analyst Tools--> Surface--> hillshade. This tool created shading in areas with elevation differences as shown in Figure 4. This provides more depth with the contour lines. Along with the contour lines were labels of the contour increments converted as feature-linked GDB annotations. 

Figure 3. Parameters for Contour tool

Figure 4. Hillshade tool used on LiDar rasters

The next step was to create two different grid systems for the maps that was mentioned above. First, the UTM grid was created with a Measured Grid. This was found under the Layers Data Frame Properties and clicking on Grids. The interval spacing was set to 50 meters to insure a large scale measurement of the area, as shown in Figure 5. The DD Grid was set to a Graticule Grid in order to measure the in DD. The increments for the DD Grid were set to 3.0'', as shown in Figure 6. Lastly, map elements were added to each map to help interpret them.

Figure 5. UTM Grid system

Figure 6. DD Grid system

Results/Discussion
Figure 7. Shows the UTM Navigation Map and Figure 8. Shows the DD navigation Map. The Area of study was outlined with red. Contour lines and elevation were used to help distinguish the variability in landscape. The color brown was used for contour lines specifically since it is the universal color used in topographic maps. Annotations were used to help distinguish the 3 meter interval of the contour lines. The representative fraction of the map was 1: 3,600. Representative fraction is map scale vs. reality. Meaning 1 is representing a unit of measurement on the map and 3,600 is the representation in the real world. Since RF's don't have units associated with them it could mean anything; however, since we are measuring in meters it is best to use centimeters to distinguish the distance. So, 1 centimeter on the map is equivalent to 3,600 in real life that could then be converted to meters meaning 1 meter on map equals 36 meters in real life. Using this and the pace count one could estimate how far an area would be to get to. Using a UTM grid for Figure 7. The spacing was set to 50 meters to show clear image of the location and space.

Figure 7. UTM Navigation Map 

Figure 8. Depicts the Decimal Degree Map. This map is the same as Figure 7, except for the grid system depicting a 3.0'' interval, thus creating a different way to navigate the area.

 

Figure 8. DD Navigation Map

Conclusion

Maps can be created of the same area describing the same thing in different ways. The two maps created are identical but since they run on different grid systems the navigational use could vary. This is important when creating a navigation map to best fit the needs of what the criteria is. Also, considering the different map projections and GC can have effects on your map distortions and depictions.

References:

http://www.wa6otp.com/utm.htm 

Professor Hupy

Priory GDB