Table of Contents
- Mapping Earthquakes in Northern California
- Setting Up Your Workspace
- Downloading Data from Natural Earth
- Download Data from the Northern California Earthquake Data Center (NCEDC)
- Skill Drill: Download Data from the United States Census Bureau
- Adding California as a Basemap Layer
- Skill Drill: Adding the Humboldt County Boundary as a Basemap Layer
- Adding XY Data
- Changing the Map Projection of the Data Frame
- Representing Earthquake Magnitude Using Graduated Symbols
- Changing the Map Size and Position
- Creating an Inset Map
- Inserting A Map Title
- Inserting a Map Legend
- Inserting a North Arrow, Scale Bar, and Acknowledgments
- Exporting your map as a PDF file
Adding California as a Basemap Layer
In geospatial science, a basemap refers to a collection of data layers that are used to create a background for the map. The purpose of a basemap is to provide context for the primary data, both spatially and thematically. Typical basemap layers include roads, administrative boundaries, and aerial imagery. In this activity, the state and county boundaries serve as the basemap layers.
Locate ArcMap on your computer and launch the software. If you are using Microsoft Windows 10, click the windows button and type ArcMap to find the desktop application. Launch the ArcMap software.
When you first launch ArcMap, a window appears that gives you the option to either open a blank map or to open any of your recent map documents. Choose to open a blank map document.
The ArcMap user interface has three main windows that you use on a regular basis, the Table of Contents, the data frame, and the Catalog Window. The Table of Contents displays a list of data frames and map layers loaded into the map documents. The data frame, sometimes spelled dataframe, represents the layers in the form of a map and defines the map extent. The Catalog Window displays a hierarchical view of folder connections and data in the form of a Catalog Tree.
The icon for the catalog window looks like a yellow file cabinet. If your catalog window is missing, you can find the icon on the toolbar across the top. Click to open it back up.
In this step, you will start by working with the Catalog Window. The catalog window is where you manage your geospatial data in ArcMap. Start by clicking on the Connect to Folder button. Navigate to your workspace folder, Earthquake_map, on your local hard drive.
In this step, it is essential that you select your primary workspace folder, Earthquake_map, to add it to the Catalog Window. When ready, click OK.
Once you add your workspace folder to the Catalog Window, expand the folder by clicking on the plus sign. You should see your three subfolders inside. Expand the original folder to view the contents. This display of folders and files within the Catalog Window is sometimes called the Catalog Tree.
In a previous activity, you learned how to add data to ArcMap. Add the states and provinces layer to the map.
In a previous activity, you learned how to use various zoom tools. In ArcMap, zoom to the State of California and surrounding areas. Try to set your map so that California takes up most of the space.
Because California is the primary geographic extent for your earthquake maps, you will want to be able to distinguish California from the other states. You will do this by creating a new shapefile with California as the only polygon feature.
In a previous activity, you learned how to directly select features on the map using the select features tool. Use the tool to select the State of California. On the Tools toolbar, click the Select Features tool. The icon looks like a white arrow over a blue and white square. Then click on California. When you have a feature selected in ArcMap, you have the option to export it as a new shapefile. With California selected, right-click on the states and provinces layer in the Table of Contents. Select, Data, then Export Data.
When the Export Data window opens, you will see some options. Next to Export, be sure it says Selected features. Next, click the yellow file folder icon and browse to your Working folder.
Never accept the default output location in ArcMap. Always browse to the folder location you intend to use. This step will help prevent lost data.
Next to Save as type, choose Shapefile. Name the file “California” and click Save, then click OK. When ArcMap asks if you want to add the exported data as a map layer, click Yes.
The California layer gets added to the Table of Contents. On the map, California remains selected. Clear the selection by clicking on the Clear Selected Features button. Your map document now has two layers, one representing the State of California and one that currently displays the surrounding States and Mexico.