Introduction
Land navigation with a map and compass is a useful
skill because as we learned last week you cannot always rely on technology.
Being able to use a map with a compass removes any need for electronics and
lightens the load being brought into the field. The kind of map used for
navigation is important because if the map is too busy (containing too many
features) it will be hard to read and almost useless. A map suitable for land
navigation can be created using very few layers.
The maps created will represent a specific
location located in southern Eau Claire, WI, the Priory. The landscape of the
Priory is dynamic with the main building being built on a steep plateau. The
Priory is presently a dormitory used by students of UW-Eau Claire and is the
new home of the UW-Eau Claire’s Children’s Center. A navigation course has been
established in the woods surrounding the Priory which will be utilized later on
in the semester. The maps created in this exercise will be used when we travel
to the Priory to practice our navigation skills.
For this
exercise two maps were constructed; one using a geographic coordinate system
(GCS) and another using a Universal Transverse Mercator (UTM) coordinate
system. These maps were created using ArcMap 10.2 with map data provided from
the instructor of the course.
Methods
Data Collection
The first step in creating the maps was data
collection. As mentioned above data was provided for the maps with the task of
selecting pertinent layers to be included in the map. Numerous layers were provided
by the instructor but most of the data was not useful. I chose to use the 5
meter contour lines developed from a USGS DEM, an aerial image to provide an
accurate representation of the elevation for the Priory, and a Navigation
Boundary which shows the maximum extent of the navigation course.
I chose these data sets to accurately display the
elevation changes over space at the Priory while also showing what the surface
actually looks like from above. The contour lines are not as cluttered as a 2
foot interval data set which was provided. A digitized contour map was also
provided but was excluded because of how the contour lines were overlaid on
plain background which does not accurately display the land. Another data set
including a No shooting boundary was excluded. This boundary will be used at a
later time when paintball guns will be include in the navigation course but for
now it can be left off the map.
Map Creation
Once the 5 meter contour lines, the aerial image,
and the navigation boundary were displayed in ArcMap each data set was
projected to the UTM zone 15 system. UTM is a projected coordinate system which
uses a 2-dimensional Cartesian coordinate system to give locations on the
surface of the Earth. UTM system is not a single map projection but a
collection of 60 zones(figure 1).
 |
| Figure 1. A map of the world with all 60 UTM zones overlaid. Each zone covers a 6 degree band of latitude on the secant transverse Mercator projection. |
UTM zone 15 was chosen because of how Eau Claire,
WI is located close to the central meridian of the zone and the zone is
measured in meters instead of degrees like how the WGS 1984 system is measured.
WGS (World Geodetic System) 1984 was used for the
second map containing the same layers as the one using the UTM zone 15 system.
WGS 84 is a standard for use in cartography, geodesy, and navigation and is the
reference coordinate system used by the Global Positioning System. This system
is the result of a unified geodetic system for the whole world because of lack
of inter-continental geodetic information, the inability of the large geodetic
systems to provide a worldwide geo-data basis, a need for global maps for
navigation, aviation, and geography, and other reasons. Figure 2 below shows
the WGS 84 system.
 |
| Figure 2. Image of the world displayed in the WGS 84 coordinate system. Notice how this image and the UTM image are similar. The WGS 84 system is measured in Degrees whereas the UTM is in meters. |
This projection was chosen because it is the
system used by the Global Positioning System which will be utilized by using a
handheld GPS for part of the navigation.
Grid Creation
For the purpose of the navigation maps we were
instructed to use an 11x17 inch landscape orientation. In order to do this the
layers were displayed in ArcMap using Layout View. To do this select change layout in the layout toolbar.
Click the North American (ANSI) Page
Sizes tab and finally the Tabloid
(ANSI B) Landscape.mxd. This template has a default 11x17 inch size (Figure
3).
 |
| Figure 3. The Select Template window with the Tabloid (ANSI B) Landscape.mxd template highlighted. This template is defaulted to 11x17inches which will make for a large map but one that is still easily carried. |
After the layout is selected the map can be
repositioned and adjusted to suit the user and features such as a title, scale
bar, north arrow, and other map features can be added. For the purpose of
plotting the navigation points a grid must be used to provide accurate
placement of points. Two grids were created, one for the UTM zone 15 projection
and one for the WGS 84 system. The UTM zone grid is in meters and the WGS grid
is in degrees.
To create the grids there are many steps which must
be done.
1.
With the map positioned within the
layout view navigate to properties of
the data frame
2.
Click the Grids tab and then New Grid…
3.
Within the Grids and Graticules Wizard
pick either Graticule or Measured Grid. Then name the grid. For
the purpose of these instructions I’ll be using the Measured Grid. Figure 4 will show the windows that should be on the screen at this point.
 |
| Figure 4. Windows showing the first three steps of grid creation in ArcMap with red numbers indicating at which step to click or make adjustments. |
4.
Click next and then properties to select a coordinate system
5.
Then decide on an interval for the
grid. For my grid I chose a 50 meter interval on the X and Y axis
6.
After the interval is chosen the user
is able to make changes to the aesthetics of the grid. Once finalized click Finish in the wizard to make the grid
appear in the layout.
Both grids are created in a similar fashion with
the only major difference being the coordinate system that is chosen within the
wizard.
Results
The resulting maps of the study area with the grid
and layers are below. Figure 5 is the map with the UTM zone 15 system and
figure 6 is the WGS 84 system.
 |
| Figure 5. Priory map with 5 meter contours, a transparent aerial image and a navigation boundary. The grid on the map is measure in meters with 50 meter intervals on the X and Y axis. |
 |
| Figure 6. Priory map with 5 meter contours, a transparent aerial image and a navigation boundary. The grid on the map is measure in degrees with 2 second intervals on the X and Y axis.. |
Compass Navigation
In order to use the maps created to their fullest
potential the use of a compass for navigation must be learned. A standard
compass (figure 7) will be utilized for navigation at the Priory. To use the
compass there are a series of steps which will get the most out of what the
compass can do.
 |
| Figure 7. A compass with many features that is identical to what will be utilized for the orienteering activity. The rotating Housing With Degree Dial will be referred to as a "bevel" later in the directions. |
1.
Place the compass on the map having
the direction of travel arrow (DTA) pointing in the desired direction of travel
from your starting point to the ending point.
2.
With the compass still on the map
rotate the bevel so that 0 degrees on the bevel is pointing to the Northern
part of the map. Use the grid lines to help point the bevel north.
3.
Finally, take the compass from the map
and hold it steadily in front of one’s self. Rotate until the red end of the
magnetic arrow fits into the holler orienting arrow. This is commonly referred
to as being “red in the shed”. As long as you maintain this red in the shed you
will be moving in the desired direction of travel to approach the destination.
Discussion
The creation of the maps and grid will prove
beneficial for navigation practices because of how easily readable the maps
are. With only showing an aerial image and contour lines as well as a
navigation boundary anyone should have an easy time navigating around the
Priory.
A legend was not included on the maps because the
only main feature that was necessary to label was the contour lines. The
navigation boundary, although being a layer on the map, provides nothing more
than an extent for the map similar to a state or county boundary. The contour
lines are clearly labeled in the heading of the maps as being 5 meter
intervals.
With the aerial image being more transparent it is
easier to plot points than if it were to be its full color. Having it
transparent also allows for the contour lines to stand out showing the landscape
more clearly.
Conclusion
Both maps were created encompassing the Priory in
southern Eau Claire, WI as the study area showing 5 meter contour lines, an
aerial image, and a navigation boundary. These maps will be utilized in an orienteering
activity at a later point in the semester.
The maps look good on a computer screen but once
printed out and worked with in the field will their true strength be known. It
is easy to make a map look good on a computer but nothing can truly emulate a
hard copy of a map besides a hard copy. By knowing the assignment and being
familiar with the region I selected what I believe to be pertinent data for the
map.
No comments:
Post a Comment