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Geocode voters

Your candidate needs detailed demographic information about eligible voters in Howard County, Maryland. You'll start by creating a map of the voters broken into census tracts, which are subdivisions usually numbering between 1,500 and 8,000 people. These smaller divisions will facilitate your research about Howard County voters. Finally, you'll geocode, or geographically locate, a file of addresses, so you can begin to identify the locations of like-minded voters.

Map your district

Howard County is an affluent area nestled among the rolling hills between Baltimore and Washington, D.C. According to the Howard County government page, the 2010 census counted more than 280,000 residents. Median household income is nearly $107,000, and the region is home to more than 50 federal agencies, major universities, defense contractors, and Fortune 500 companies.

First, you'll map Howard County and its boundaries. Using ArcGIS Online, you'll create a map of the area and add census tracts.

  1. Sign in to your ArcGIS organizational account.

    If you don't have an organizational account, you can sign up for an ArcGIS free trial.

  2. At the upper left of the window, click Map.


    A new map opens.

  3. In the search box, type Howard County, Maryland and click the result in the search window.

    Howard County search

    The map zooms to central Maryland, and a pop-up indicates the county location.

  4. Close the Search result pop-up.

    Next, you'll add a layer from the Living Atlas of the World, which is a vast collection of authoritative and ready-to-use geographic information. Specifically, you'll add a layer of census tracts for the United States. Then, you'll filter the layer to show only tracts within Howard County.

  5. On the ribbon, click the Add button and click Browse Living Atlas Layers.

    Browse Living Atlas Layers

    The Browse Living Atlas Layers window shows a list of all Living Atlas layers. You'll filter the list by map extent and category to more easily find the layer you want.

  6. Verify that the Within map area box is checked.

    Within map area

  7. Under Caterories, choose Boundaries.


    The list is narrowed down, but still quite large. You can also search for specific layers.

  8. In the search box, type census tract and press Enter.

    The US Census Bureau reports data by various geographic units. Census tracts, the most appropriate unit for this lesson, are designed to be fairly homogeneous with respect to demographic and economic conditions.

  9. For USA Census Tract Areas, click Add to map.

    Add to map

    The layer is added to the map. The name of the layer appears in the Contents pane.

  10. In the Browse Living Atlas Layers window, click the back arrow to return to the Contents pane.

    Census Tract Areas

    The USA Census Tract Areas layer is displayed in pink, showing boundaries for census tracts. The layer covers the entire United States, although you currently only see Howard County and the surrounding area. You'll filter the layer to show only data for Howard County, Maryland.

  11. In the Contents pane, point to the USA Census Tract Areas layer and click the Filter button.

    Filter button

    A filter uses logical expression(s) to find features in a layer on the basis of attribute values in its table. The features of interest will appear on the map; all others will be hidden (but not deleted). Expressions use the general form of <Field name> <condition> <Value or Field>. In this case, you want all the census tracts in Howard County, so your expression will read "County is Howard."

  12. In the Filter window, ensure that County is set in the list of field names.
  13. Leave the condition set to is.
  14. In the input box for attribute values, type Howard.

    Filter expression

  15. Click Apply Filter and Zoom To.

    Howard Counties

    Applying this filter narrows your data significantly, but six other counties in the United States have the same name.

  16. In the Contents pane, point to the USA Census Tract Areas layer and click the Show Table button.

    Show Table button

    According to the table, Texas, Nebraska, Arkansas, Missouri, Iowa, and Indiana also have counties named Howard. To limit the data to Maryland, you'll add another expression to the filter.

  17. Point to the USA Census Tract Areas layer and click the Filter button.

    You already defined a filter for this layer, so the Filter window looks different than it did before. Your first expression is displayed on the View tab.

  18. On the Edit tab, click Add another expression.

    Another query box is added to the Filter window.

  19. In the list of field names, choose State. Leave the condition set to is. Under the input box for attribute values, choose Unique.

    This option provides a list of valid attribute values for the selected field.

  20. From the list of attribute values, choose MD (the abbreviation for Maryland).

    MD attribute value

  21. Click Apply Filter and Zoom To.

    Filter result

    The layer now displays only the data for Howard County in Maryland. The attribute table for the USA Census Tract Areas layer contains 55 features in the table. You can verify that only Maryland's Howard County appears on your map by looking in the State column and scrolling to the bottom.

  22. In the Contents pane, point to the USA Census Tract Areas layer and click the Hide Table button.

    Hide Table button

    You're now ready to download data for voters in southern Howard County.

Geocode voters

In this section, you'll download a CSV file that lists the names and addresses of 950 potential voters. Then you'll geocode their addresses so you can research their lifestyles and living standards through Tapestry Segmentation. Geocoding is a GIS operation for converting street addresses to spatial data so that they can be mapped.

  1. Go to the Map Voter Data to Plan Your Campaign group.

    This group contains a CSV file of names and addresses for voters in southern Howard County.

  2. Click the thumbnail image for the CSV file.

    Depending on your browser, the CSV file may appear on your download bar, or you may be prompted to open or save the file.

  3. Download the Howard_County_Voter_Data CSV file to a location on your computer. Remember the location so you can browse to it.
  4. On the ribbon, click Add and click Add Layer from File.

    Add Layer from File

    The Add Layer from File window opens. ArcGIS Online supports CSV files with up to 1,000 records.

  5. Click Choose File (or your browser's equivalent command). Browse to the folder where you saved Howard_County_Voter_Data.csv.
  6. Click the file to select it and click Open.
  7. In the Add Layer from File window, click Import Layer.

    You can also drag a CSV file directly to a web map from your computer.

  8. In the Add CSV Layer window, confirm that Addresses or Places is selected.
  9. If necessary, for In, choose United States.

    Add CSV Layer

  10. Click Add Layer.

    Address points layer

    The 950 points displayed on the map represent homes of individual (and fictitious) voters.

  11. Click any point to see information about that voter.

    Address points pop-up

    In addition to the voter name and address, the new layer includes gender, volunteer status, and donations.

  12. Close the pop-up.

    By default, the points are assigned unique colors on the basis of their name. Other drawing options are shown in the Change Style pane. For this map, the individual names aren't important, so you'll give all the points the same symbol to show only the location of each voter.

  13. In the Change Style pane, for Choose an attribute to show, choose Show location only.

    Show location only

  14. Click Done.

    Symbolized address points

    The data displayed on the map can now be matched with Tapestry.

Save the map

Next, you'll save your map and assign it a title, tags, and summary to make it easy to find and identify later.

  1. On the ribbon, click the Save button and choose Save As.

    Save As

  2. In the Save Map window:
    • For Title, type Howard County, Maryland, Census Tracts.
    • For Tags, type Howard County, Census, and press Enter.
    • For Summary, type Research for a political campaign in Howard County.

  3. Click Save Map.

    The map is saved with the specified title, tags, and summary. (Once you've saved your map, it appears in My Content, which you can access by clicking the Home menu and choosing Content.)

You now have a map combining voters and census tracts in Howard County. You created this map to prepare for the next lesson, where you will analyze data and add lifestyle and political information. This map will also serve as your first slide in the final lesson, where you will create a four-slide presentation.