In the previous lesson, you became familiar with the locations of volcanoes and high hazard lava flow zones on the island of Hawaii. For planning purposes, it might be useful to know where these areas are in relation to highways (which are already on your map) and emergency shelters (which are not).
A lot of information that is potentially spatial in nature is locked away in spreadsheets and text files. If this information is properly formatted, it can be added to ArcGIS Online and turned into map layers. All you need are well-defined street addresses or pairs of latitude-longitude coordinates.
In this lesson, you'll add a CSV file of emergency shelter addresses to your map. A CSV (comma-separated values) file stores table data in a plain text format. It's an import/export format commonly supported by spreadsheet and database applications.
Download and view a CSV file
- Go to the Get Started with ArcGIS Online group.
If you didn't create an ArcGIS Online organizational account to save your work in the previous lesson, be sure to keep your map open. If you close your map, you may lose your work.
- Click the Hawaii Emergency Shelters CSV thumbnail.
Depending on your browser, the CSV file may appear on your downloads bar or you may be prompted to open or save the file.
- Open the file with your default application for opening CSV files, such as Microsoft Excel.
- If necessary, widen the columns by dragging or double-clicking their edges.
Each row in the table represents an emergency shelter. (On the island of Hawaii, most shelters are schools.) The address columns allow the table to be interpreted as spatial data.
If you're viewing the file in a text editor, you'll see the same information formatted as text separated by commas. ArcGIS Online will accept it either way.
- In the application in which the CSV file is open, click the File menu and choose Save As. Save the file as EmergencyShelters.csv to a location on your computer.
- If the file is open in Microsoft Excel, you’ll be prompted whether you want to keep the workbook in CSV format. Click Yes.
- Close the application in which the CSV file is open. (If you’re prompted to save changes again, click Don’t Save.)
Add the CSV file as a layer
You downloaded this CSV file from ArcGIS Online. You can get CSV files from many other public servers or convert them from other file types. You can also make them by copying and pasting information from web pages or other sources.
- Return to the browser window with your Hawaii map. (If you created an account and saved your map, open your map from your My Content page.)
- On the ribbon, click the Add button and choose Add Layer from File.
- In the Add Layer from File window, click Choose File (or your browser's equivalent command). Browse to the location where you saved EmergencyShelters.csv.
- Click the file to select it and click Open.
- In the Add Layer from File window, click Import Layer.
You can also drag a CSV file directly into a web map from your computer.
When you add a CSV file with location information (street addresses or latitude-longitude coordinates), the map viewer locates the features on the map. If you add a CSV file that doesn't contain location information, a table is added instead. In this case, the file is recognized as containing street addresses.
- If necessary, in the Add CSV Layer window, for Country, choose United States.
Depending on your organization’s configuration, Country may default to a value other than World. (For example, it may default to United States.)
In the table, the Field Name column lists the field names (column headings) from the CSV file. In the Location Fields column, these field names are matched to appropriate categories of address information for the specified country. The ADDRESS field, for example, is correctly interpreted as containing street addresses. The CITY field is correctly interpreted as containing city names.
- Scroll to the bottom of the window to confirm all the field names are being interpreted correctly.
Your CSV file may contain street addresses stored under field names that ArcGIS Online doesn't recognize as address fields. You can apply the interpretation yourself by clicking the Location Field value next to the field name and choosing the appropriate location information from a drop-down list.
- Click Add Layer.
On the map, a point symbol is drawn at the address of each shelter. (As you can see from the legend, most or all of the shelters are schools.) By default, the points are assigned unique colors on the basis of name. Other drawing options are shown in the Change Style pane.
For this map, the individual names aren't important. You're interested in the shelters as shelters, so you want to give them all the same symbol.
- In the Change Style pane, under Select a drawing style, click Select for the Location (Single symbol) style.
In the Change Style pane, the Location (Single symbol) style now has a check mark to show that it's selected. On the map, the shelters are drawn with a single symbol.
In the next section, you’ll apply a different symbol that more specifically represents emergency shelters, but this symbol will do for the moment.
- At the bottom of the Change Style pane, click Done.
- In the Contents pane, point to the Emergency Shelters layer. Click the More Options button and choose Rename. Rename it Emergency Shelters with a space between the words.
Symbolize the shelters
You'll change the default symbol to something that better represents emergency shelters.
- In the Contents pane, point to the Emergency Shelters layer and click the Change Style button.
In the Change Style pane, the currently selected drawing style is Location (Single symbol). This is the style you selected in the last section.
- Click Options for the Location (Single symbol) drawing style.
- Under Showing Location Only, click Symbols to change the symbol.
A symbol palette opens, showing a variety of symbols that belong to the default Shapes category of symbols. ArcGIS Online also has many other symbol categories.
- Click the arrow next to Shapes and choose the National Park Service category.
- In the National Park Service category, find the symbol with a white cross on a black background and click it to select it.
- Change the symbol size to 12 px (pixels) and click OK.
The symbols are updated on the map.
- In the Change Style pane, click OK and click Done.
The new symbols are intuitively recognizable as emergency shelters. Their strong black and white colors help them stand out from the reds and oranges of the hazard zones.
Remember that you haven't saved your work for this lesson. To save your work, you can sign up for an ArcGIS free trial to receive an ArcGIS Online organizational account. If you want to continue without signing in, be sure to keep the map open in your web browser.
When you explored the Hawaii Lava Flow Risk map in the first lesson, you began by opening pop-ups for the volcanoes and lava flow hazard zones. Configuring pop-ups to present useful information is an important part of making good maps. That will be your task in the next lesson.