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
Download Data from the Northern California Earthquake Data Center (NCEDC)
UC Berkeley Seismological Laboratory created the Northern California Earthquake Data Center. Using the Chrome browser, navigate to the Northern California Earthquake Data Center (NCEDC) website at http://ncedc.org/ncedc/catalog-search.html. The catalog has quite a few search settings which at first may seem confusing. In this activity, we will not cover all of the details related to the settings. To find out more about how to use this website and to learn about the options available, you can click the help link to read the additional documentation. For the input catalog, choose USGS NCSN Catalog 1967 – Present. For the output format, pick NCSN catalog in CSV format.
For the earthquake parameters center the values from the table below:
Leave all other Earthquake Parameter settings not mentioned here as default. Under Output Mechanism, select Send output to an anonymous FTP file on the NCEDC.
When you are ready, click Submit request. In the Chrome browser, the results will load in a new tab. Under “output can be downloaded from:” click the link next to URL.
The next page will display the data in CSV format. You will need to save the results to your Original folder.
In the Chrome browser hit Ctrl S to save. Browse to your Original folder. For the filename, enter “earthquake2017.csv”. Next to Save as type, choose All files. When you are ready, click Save. In Microsoft Windows navigate to your original folder and open the earthquake 2017 CSV to view the results. By default, a CSV file should open in Microsoft Excel.
If for some reason, the CSV file does not open in Microsoft Excel, right-click and select Open with, then choose Microsoft Excel as the default program.
When opened in Microsoft Excel, the CSV file appears as a table. The commas in the data create columns, also called fields, in excel. A row, also called a record, represents each earthquake. In this instance, the top row is different from the remaining records. It is made up of column headers, sometimes called field names. When working with geospatial data, this format is critical. The first row of any geospatial data table must contain the field names. You will learn more about these types of tables in a later chapter.
Go ahead and close the CSV file in Microsoft Excel. In a later step, you will use the CSV file in ArcMap, and it is important not to have it opened in two places at once.