GIS 1 - Lab 2: Projections

Goal

The main purpose of the projections lab is to show the differences between Geographic Coordinate Systems (GCS) and Projected Coordinate Systems (PCS.) Each is applied to GIS data provided by the instructor with various issues involving one or both coordinate systems.

Tools and Skills Utilized

• create map layout with multiple data frames

• attribute table

• select features

• project

• define projection

• change projection

• adding and showing labels, titles, other map components

Methods

Part One: Setting World Predefined Projections on Data Frames

Included in Ex.1 are the following world-wide projections: Geographic Projection (WGS 1984), Mercator, Sinusoidal, Equidistant-Conic, and Azimuthal Equidistant projections.

Section One: Add Layers to the Data Frame

By adding shapefiles to a new map document, the user is expected to create a map layout using different projections of the world.

Section Two: Build another Data Frame

In order to create a aesthetically pleasing map, the assembly and organization of multiple data frames in the layout tab is necessary. Each data frame exhibits a different projection to display the world's continents.

Part Two: Setting State Level Predefined Projections on Data Frames

Section One: Create a Data Frame for Wisconsin Data

By creating a new data frame with the United States data and select out Wisconsin by use of the search by attributes in the attribute table. After saving the Wisconsin selection, the user should set the data frame coordinate system to UTM, NAD 1983, Zone 16N. This focuses the projection on this specific zone that shows Wisconsin.

Section Two: Explore Projection Information

A portion of this section is dedicated to confirming the users' comprehension of the exercise in addition to the creation of a new data frame in ArcMap. By adding the stroads_miv5a and states.shp files to the States data frame the two shapefiles overlay correctly. These two sets of data have been accurately projected via on-the-fly projection software. The user must project the states file to the same projection as the stroads_miv5a.shp. This is done by using the Project Tool from the side toolbox. Changing the data frame properties to change it to North American Lambert Conformal Conic is necessary to make sure the projections line up correctly. Noted is the difference in the data frame projection and the shapefile projections, yet they still cooperate in the map.

Part Three: Create a Map

This part is set up to allow the user to assemble their layout of world, Wisconsin, and United States projections. Tools used in this section include basic cartographic tools such as labels, titles, scales, north arrow, author name, date of creation, and a neatline.

(An example is shown below as figure 1)

Part Four: Identifying and Fixing Projection Problems in GIS Data

Two features in this part will have different projection problems. The users overlay them and diagnose/solve the projection issues.

Provided for this portion of the exercise is data from the Central_Wisconsin folder. The Central_WI_Cts.shp is added first, then project it correctly. The issue with this particular shapefile is that it is missing both a coordinate system and projection. The metadata is given as GCS: North America_1983 and datum: North America_1983. The user is left to differentiate which system to appropriately utilize. The most appropriate choice for the geographic coordinate system is the GCS_North_American_1983. The NAD_1983_StatePlane_Wisconsin_Central_FIPS_4802 projection coordinate system is the most specific focus on the area in question.

The next diagnostic exercise is the Lower_Chip_strms.shp. This shapefile had the correct GCS but lacked a specific projection to central Wisconsin. In order to sort out the correct projection, the user must add the appropriate projection to the river polyline feature (the Lower_Chip_strms.shp.) The correct projection to add to this file is the same PCS as the Cts shapefile, NAD_1983_StatePlane_Wisconsin_Central_FIPS_4802. This associates the data to the correct spatial reference in order to project perfectly.

The user is then expected to create a map layout that shows the rivers and streams that flow throughout the counties of central Wisconsin. (shown in figure 2 below) Aspects that should be included are the title of the map, county labels, lines of rivers, a legend, north arrow, neatline, author, and date completed.

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Results

Figure 1 illustrates various projection coordinate systems and their appropriate scale levels.

Figure 2 shows the distribution of streams and rivers within central Wisconsin.

Sources

U.S. Census Bureau, 2010 Census. 

Instructions for the lab were provided by my professor, Dr. Curtis and colleagues from the Geography and Anthropology Department at the University of Wisconsin Eau Claire.