Lab 4: Development of a Field Navigation Map

Introduction

On November 4th, 2017 we will be going out to The Priory to conduct Lab 8: Navigation with Map and Compass where we will learn to navigate with a map and compass. In preparation for that lab, I will develop a Field Navigation Map. I will create two maps, one with a Geographic Coordinates grid and one with a UTM grid, in ArcMap using data provided by Dr. Hupy. The Priory Study Area is shown in reference to UWEC Phillips Science Hall in Image 1.

Image 1: UWEC The Priory

Background

Coordinate Systems

Since the earth is round, it is impossible to perfectly accurately represent the earth's surface on a flat map. However, clever coordinate systems are employed to more accurate representation. There are an innumerable amount of coordinate systems and projects available based on location, scale, and map purpose, each with its own pros and cons. In order to create my navigation maps, I employed a geographic coordinate system and a Universal Transverse Mercator zone system.

Geographic Coordinates

According to Esri, a geographic coordinate system (GCS) utilizes a three-dimensional sphereical surface to define locations on the earth. Each point is referenced via its latitude and longitude values, angles measured (often in degrees) from the center of the earth to that point. 

The GCS I used to create my maps is GCS_WGS_1984.

Figure 1: Globe with latitude and longitude values.

Universal Transverse Mercator

Universal Transverse Mercator (UTM) is a coordinate system where the globe is divided into 60 north and south zones with an independent coordinate system whose origin is the the equator and the zone's central meridian. The zones span 6 degrees of longitude. To prevent negative numbers, the system utilizes a false easting of 500,000 meters.  Figure 2 shows the UTM zones across the conterminous U.S.

The UTM coordinate system I utilized to create my maps in this project is NAD_1983_UTM_Zone_15N.

Figure 2: UTM zones across the conterminous U.S.

Methods

Data Provided

In ArcCatalog I explored the data provided which included a USGS map of Eau Claire, two aerial photographs of Eau Claire, a DEM of western Wisconsin, elevation labels, three Lidar rasters of the study area, a polygon delineating the study area, as well as 2ft contours of the study area. Between the 11 data files provided, there are four coordinate systems represented as well as 3 undefined data files. Follow this link to preview the data provided: https://universityofwieauclaire-my.sharepoint.com/personal/kubishme_uwec_edu/_layouts/15/guestaccess.aspx?docid=05b256c299eb34266a937f20f727813cc&authkey=AbuWcL0kHrcMAfKc1F4o5nU

Data Preparation

As noted, the data provided were not all in the same coordinate systems and so my first step in preparing the data is to put them all in the same coordinate system. In ArcMap, I added Lidar062609NE, which has a spatial reference of NAD_1983_HARN_WISCRS_EauClaire_County_Feet, to my data frame. I then added LidarNE and LidarNW, whose spatial reference is undefined. Since they lined up next to Lidar062609NE so well and were probably collected during the same survey, I can assume that they should have the same spatial reference. In the search window I search "project" and use the tool "Define Projection" to define both LidarNW and LidarNE spatial reference as NAD_1983_HARN_WISCRS_EauClaire_County_Feet.

I would like these three Lidar rasters to be combined into a single raster, so in the search window I search "Mosiac To New Raster." I use all three lidar data sets to create a single data set named "LidarPriory". Be sure that the specs of the old raster match the new one: Pixel Type should be 32 Unsigned and the Number of Bands should be 1.

Using the "Hillshade" tool I then created a shaded relief raster from "LidarPriory". This will serve as the background for my UTM map.

I created duplicates of "Navigationboundary", "Hillshade", and "Eau_Claire_West_SE" files projected in both GCS_WGS_1984 and UTM Zone 15N. 

Layout Setup

In the Page and Print Setup window, I make sure that the paper size is 11x17in and in Landscape view.

For the UTM Map, I set up a grid with 50m spacing and selected "Hillshade" as the basemap.

For the GCS Map, I set up a grid displaying geographic coordinates in Decimal Degrees.

Results

Map 1: Global Coordinate System Navigation Map Closer Look

Map 2: UTM Navigation Map Closer Look

Conclusions

Based on my experience at UWEC's Geology Field Camps I and II, a map with an aerial photograph is extremely useful for navigating via landmarks and visualizing the larger map area. However, they are painful to record data on. Presuming that we may need to mark on these maps and that our GPS will provide location data with UTM coordinates, I selected the more neutral Hillshade background for my UTM map. This map also nicely highlights topographic changes in the landscape that the aerial map does not. The GCS map utilizes the aerial imagery. I chose not to employ contour lines because of the relatively minimal elevation changes.

During and after the field trip I will be able to access if my presumptions have been reasonable or accurate.