Field Activity #5: Development of a Field Navigation Map

Introduction

This week's activities required us to create two field navigation maps.  We will being using the map in the following weeks along with a compass to locate a number of locations withing the area of the Priory in Eau Claire, WI.  The Priory is a wooded 120 acre off campus property, with residence halls owned by the University Wisconsin Eau Claire.  The ample space makes it a prime location for a navigational training.  In addition to creating the navigation maps we will also be learning a skill called pace counting.

Dr. Hupy set up a geodatabase with a plethora of data for us to use while constructing our navigation maps.  One of the few requirements was one map had to have a grid with the Universal Transverse Mercator (UTM) coordinate system with 50 meter spacing (or finer) and the other map had to have a grid with the Geographic Coordinate System (GCS).  The only other requirement was it should be created in landscape format and sized for 11x17 paper.  The reset of the design detail was left up to us using the given data.

The UTM coordinate system is broken in to 60 different zones, each of these zones are 6 degrees of longitude wide.  The zone are also split into an northern and southern zone, the split coming at the equator.

(Fig. 1) UTM zone layout (http://www.gpsinformation.org/utm-zones.gif)

The GCS is different in the aspect it uses latitude and longitude to determine your location on the earth.  This location is stated in terms of decimal degrees, and then can be converted to degrees, minuets, seconds with simple math.  One issue with using GCS for navigation is there in no actual form of measurement to determine how far you have to or have traveled.

(Fig. 2) Geographic Coordinate System layout. (http://newdiscoveryzhou.blogspot.com/2006_08_01_archive.html)

Methods

Pace Counting

Before we started the construction of the maps Dr. Hupy discussed a basic navigation skill called pace counting.  Pace counting is knowing the distance you have walked based on the number of steps you have taken.  After the introduction of pace counting our entire class went outside to practice and learn our personal pace count for a 100 meter distance.

Using a laser distance finder Dr. Hupy gave us a 100 meter distance along the sidewalk of the Davies parking lot on campus.  The weather was not particularly pleasant, as it was raining lightly and in the temperature was around 55 degrees Fahrenheit.  Dr. Hupy had some trouble getting the distance laser finder to function properly in the beginning of our test.  After a couple second attempts he felt as though he had an accurate reading from the laser.

We were instructed to walk from point A to point B (Fig. 3) while only counting the steps we took with our right leg.  Then do the same thing when returning from point B to point A to see make sure we were consistent.  I ended up with 57 & 58 right leg paces for the 100 meter distance.

(Fig. 3) Point locations for the 100 meter distance.  (Basemap snipped from Google Maps)

Pace counting on a flat surface like the side walk gives us a good base to start from.  However, things are dramatically different when you attempt to count your paces in the woods.  Stepping over logs, going up hills, all while trying to maintain your direction are just a few of the struggles you will encounter all while trying to count and keep your paces the same distance apart as you practiced.

Map Design

We were assigned groups for this navigation project, but we were to construct maps separately.  After everyone in our group (3 of us total) had completed our map design, we had to choose which group members maps we would have printed and use for our navigation in the following weeks.

Exploring the data Dr. Hupy had provided for us was the first step for our map design portion of the exercise.  Exploring the blogs from past classes I had a good idea of what I wanted to design but I perused the data within the geodatabase.

The basemap was the first element I explored withing ArcMap.  There was a few raster images in the data to choose from.  There was a black and white aerial (Fig. 4), and color aerial taken in the fall (Fig. 5), and a scanned topographic map (Fig. 6).

(Fig. 4) Black and white aerial image of the Priory.

(Fig. 5) Color aerial image of the Priory.

(Fig. 6) Topographic map of the Priory.

After an brief examination it was clear to me the color image was definitely the one to choose.  The main factor was the level of detail which will allow my group to be able to discern different objects during our navigation.  ArcMap also has the options of importing different basemap to be used.  So using the boundary from the geodatabase we were given, I imported the Imagery basemap from ArcMap (Fig. 7).  As you can see in the photo the vegetation is very thick and green.  Our area was already experiencing fall and the majority of leaves were in the process of changing colors.  For these reasons I did not feel this map would suit our needs.

(Fig. 7) Imagery basemap of the Priory.

Contour line feature classes were the next map element I explored within the data.  I found 2 different contour line files to examine.  One had 5 meter spacing between contour lines and the other had 2 ft (.609 meters) spacing.  The 2 ft. contour file was far to tight to see any detail on the map when overlayed on the basemap (Fig. 8).  The tightness of the lines would have hindered navigation by making the map far too "busy" to understand where on the map we were located.  Additionally, I knew another set of lines was going to be added for the coordinate system grid, rendering this option useless.

(Fig. 8) Color aerial image with 2 ft. contour lines.

Examining the 5 meter contour line data, I felt the lines were spaced more appropriately (Fig. 9).  However, my initial feeling was they could possibly be spaced to far apart.  Dr. Hupy then informed us the data used to create the 5 meter contour lines was far from the best quality and he felt there was better options to  be created or found.  He made a suggestion to talk with one of our classmates, Peter Sawall who has been doing a lot of work with Lidar.

(Fig. 9) Color aerial image with 5 meter contour lines.

Talking with Peter he suggested using the latest Lidar imagery from Eau Claire County to create a new contour map from of at interval I felt was appropriate.  I told him this sounded like a great idea but I have had very little exposure to Lidar, nor do I have any idea how to process the data to produce a contour map.  Peter assured me the process was easy and he would walk me through the steps.  Peter's "walk" through was more like a solid run for me.  Peter was working on his maps at the same time so I did not take the time to slow him down to fully understand the process.  Peter has already done extensive work at the Priory so we already knew which files I needed to complete the task.  We have the current Lidar information from the county on our server at the university.  Looking at the geoprocessing history from ArcMap, we used the following tools: Create LAS Dataset, Make LAS Dataset Layer, LAS Dataset to Raster.  The final tool was the Contour tool which creates the contour lines from the raster image.  Within the Contour tool you could set the contour spacing.  I ran the tool three times setting 5 ft, 7ft, and 12 ft spacings. 

(Fig. 10) 12 ft. contour created from a raster image.

After creating the contour lines, I inspected the different spacings over my basemap of the priory.  Both the 5 ft. and 7 ft. spacings were too tight for my desired visibility of the base map.  The 12 ft. contour was exactly what I had envisioned.  Now I had to clean up the map area a little bit.  With in the data we were given was a feature class with the boundary of the area we would be navigating within.  The extent of the contour lines fell outside the navigational boundaries, so I used the Clip tool with in ArcMap to eliminate the lines which fell outside the boundary.  Eliminating the excess lines will help clean up the clutter after adding the grid lines in the next step.  I took one last look through the data and did not see any other features of interest for my map.

(Fig. 11) Color aerial image with the created 12 ft. contour lines.

Now to add the grids which will be one of the biggest aids in our navigation.  ArcMap has a built in feature to add the geographic coordinate of your map over top of the features.  To accomplish this you must be in the layout view of ArcMap.  Once in the layout view, click the Data Frame Layer properties go to the Grids tab.  From with in this tab you can create a new measured grid using your coordinate system.  Adjusting the properties after you create the grid is probably the most challenging part.  Per the recommendations of Dr. Hupy I changed the settings to have critical number in the grid in black and the beginning number (which stay the same on a map of this scale) gray (Fig 12).  I also adjusted the spacing to what I felt looked like an appropriate spacing.  The last adjustment I made was the amount of "precision" to the coordinate system labels.  After creating the grid for my UTM map, I created a new ArcMap file and added the same basemap, boundary, and contour lines and proceeded to add the grid for my GCS map.  I had to tinker around with the property settings to get the grid spacing, label colors, and precision of the numbers as I did for the UTM map.

(Fig. 12)  Layout & Design for my grid labels.

The last step was to put all of the finishing touches on the map to make it useful and cartographically pleasing.  After adding the standard map elements (title, scale, north arrow, legend, sources, my name), I added the coordinate system as well.  I decided on 2 different scales for the map not knowing exactly what we will need once we are in the field.  I adjusted the colors of the grid so they would not be as dominate of a color, allowing more of the other information on the map to stand out.  I also adjusted the transparency of the contour lines to allow more of the base map to show through.  On the GCS map I made the lines even more transparent than the UTM.  On the UTM I added labels to the contour lines.  These maps will be printed back to back so I feel having some variation between the two will be beneficial.

(Fig. 13)  UTM navigation map of the Priory.

(Fig. 14) GCS navigation map of the Priory

Discussion

Pace counting and compass navigation is not something new to me.  Years ago, I was involved with forestry judging.  We were required to navigate trails by using a compass, azimuth directions, and distances.  The difference in this exercise is I will have a map of the area and points plotted on the map and then I will have to determine the actual steps it will take to get there.  I am very comfortable walking through the woods and feel I have a good sense of distance while walking over, around, and through obstacles.

The part I am not as confidant with is the map portion.  Though I have used maps and aerial photographs for hunting and trapping purposes, I based my navigation off landmarks and just walked till I found them.   Using a map with a known distance should make the navigation easier and keep the excess wondering to a minimum.

Though  these two maps looks very similar, they are very different when it comes down to how they will be used for navigation.  My initial feeling is the UTM map will be the easier map to navigate with due to having actual distances on the grid.  The GCS map will be useful when using a GPS.  Using the GPS will give us the decimal degrees, allowing us to know exactly where on the map we are located.  After a few test pacings with the GPS I feel our group will be able to devise a good plan to know how far we have traveled.


Conclusion

Designing a navigation map when you have never used one for that purpose can pose to be a challenge.  Taking notes what others had wrote about the project and ideas from our professor proved to be the most valuable information for this exercise.  Combining that information with my preferences for maps when navigating outside, I feel as I came up with the best map I could for my level of understanding.  After the actual navigation exercise I am sure I will come up with some changes I would have made.  The best way to learn what works is done though experimentation.

Thank you

I would like to say thank you to Peter Sawall for his help with the contour line creation.  For more information about Peter hop over to his blog.