Mapping Earthquakes in Northern California

Table of Contents

  1. Mapping Earthquakes in Northern California
  2. Setting Up Your Workspace
  3. Downloading Data from Natural Earth
  4. Download Data from the Northern California Earthquake Data Center (NCEDC)
  5. Skill Drill: Download Data from the United States Census Bureau
  6. Adding California as a Basemap Layer
  7. Skill Drill: Adding the Humboldt County Boundary as a Basemap Layer
  8. Adding XY Data
  9. Changing the Map Projection of the Data Frame
  10. Representing Earthquake Magnitude Using Graduated Symbols
  11. Changing the Map Size and Position
  12. Creating an Inset Map
  13. Inserting A Map Title
  14. Inserting a Map Legend
  15. Inserting a North Arrow, Scale Bar, and Acknowledgments
  16. Exporting your map as a PDF file

Skill Drill: Adding the Humboldt County Boundary as a Basemap Layer

Using what you learned in the previous step, add the shapefile that contains the county boundaries to the map. You may get a Geographic Coordinate System Warning. Check the box that says, Don’t warn me again in this session, and click Close.

An image of the warning.
While it is OK to turn off this warning for one session. you should never turn it off permanently.

Use the direct selection tool to select Humboldt County. With Humboldt County selected, export the data as a new shapefile and save it to your Working folder. Call the new shapefile “Humboldt_County.” Add the Humboldt County shapefile to the map.

Note: the California Layer may also get selected. Don’t worry about it. When you export, it only applies to the layer on which you right-click.

When done, remove the layer that contains all the county boundaries for the United States. You should end up with three layers in your Table of Contents, one for Humboldt County, one for California, and one for the United States and Mexico.

Now is a good time to save your work. In a previous activity, you learned how to set your map document properties to store relative paths. Do this now.

An image of the Map document properties for earthquake map
Always make sure to check the Store relative pathnames to data source option. Click to view a larger sized image.

Then, save your map document to your project folder, Earthquake_Map. Call the map document “California Earthquakes.”

An image of the Save as window for California Earthquakes map document
Generally, you should avoid spaces. However, empty spaces are allowed when naming map document files (.mxd)