In this lesson, you'll create a map that shows areas of high and low median household income in Detroit, Michigan. You'll start by finding your area of interest on a new map and changing the basemap. Next, you'll add a layer of census tract boundaries from ArcGIS Living Atlas of the World, a collection of ready-to-use geographic information on thousands of topics. Then, you'll add population and income data to the layer by enriching it, and view the enriched layer's attribute table to see the data it contains. Finally, you'll style your layer to show median household income by census tract area.
Locate the study area
First, you'll locate Detroit, Michigan, on a map in ArcGIS. Then, you'll choose a basemap to provide a neutral background for your map.
- Sign in to your ArcGIS organizational account.
If you don't have an organizational account, you can sign up for an ArcGIS free trial.
- At the top of your organization home page, click Map.
A new map opens. The map extent for a new map is set to the default extent of your organization.
If you're in a new session, clicking Map opens a new map. Otherwise, it opens an existing map (the last map you were using). If an existing map opens, click New Map in the upper right corner of the page, and choose Create New Map.
- In the search box to the upper right of the map, type Detroit. In the list of suggested locations, click Detroit, MI, USA.
If your ArcGIS organization uses a custom locator that prevents you from finding this location, zoom the map to the Great Lakes region of North America. Then, zoom in to Detroit, Michigan.
The map zooms to Detroit and shows some of the geographic features of the city, including its close proximity to the Detroit River and the city of Windsor in Canada.
Every new map starts with a basemap, which provides geographic context for the data you want to display on the map. This lesson assumes that the default basemap is Topographic, but your organization may use a different default. The colors, labels, and features of the Topographic basemap may hide some of your data, so you'll choose a more neutral basemap.
- On the ribbon above the map, click the Basemap button and click Light Gray Canvas.
The map updates with the new basemap.
If your organization has configured a custom gallery and you don't see this option, click the Add button and choose Browse Living Atlas Layers. In the search box, type Light Gray and press Enter. Locate and select World Light Gray Base and click Use as Basemap.
Add a Living Atlas layer
Next, you'll add a Living Atlas layer that shows census tract boundaries. United States census tracts divide state counties into smaller geographic areas, which are useful for revealing local spatial patterns.
- On the ribbon, click the Add button and click Browse Living Atlas Layers.
The Living Atlas pane opens. You can filter the list by specific categories to more easily find the layer you want.
- In the search box, click the Filter button. In the Filter pane, click the drop-down arrow for Categories. Expand Boundaries and click Administrative.
The filtered list on the left updates to display results for the administrative boundaries filter. The list is narrowed down, but still quite large. Next, you refine your search within this category by searching for Census layers within the category.
- In the search box, type census and press Enter.
- Click USA Census Tract Areas and click Add to Map.
The layer is added to the map.
- In the Filter pane, top right corner, click X to dismiss the filter.
- In the Search pane, click the Back arrow to return to the Contents pane.
The name of the layer appears in the Contents pane.
- Pan the map so that Detroit is in the middle of the map. Then zoom out, if necessary, until you can see at least Farmington Hills in the upper left corner and Roseville in the upper right corner. (Use the image below as a guide.)
If your map has a different extent, some of your results may be slightly different than what is shown in the lessons. For meaningful analysis results, make sure that your map shows several census tract areas surrounding Detroit.
The census tracts layer is displayed in pink, showing boundaries for census tract areas of various sizes and shapes in the Detroit region. The census tracts layer covers the entire United States, even though you only see Detroit and the surrounding area.
Enrich the layer
Next, you'll enrich your census tracts layer with population and income data using the Enrich Layer spatial analysis tool. Analysis tools help you answer questions and make important decisions using more than simple visual analysis.
- On the ribbon, click the Analysis button.
- In the Perform Analysis pane, click Data Enrichment and click Enrich Layer.
The Enrich Layer tool opens. This tool enriches data by getting facts about the people, places, and businesses that surround data locations.
- For Choose layer to enrich with new data, choose USA Census Tract Areas.
Next, you'll choose the variables with which to enrich this data.
- Click Select Variables.
The Data Browser window opens. The Data Browser allows you to browse and search for detailed demographic information, or variables, about a specific country or category, including population, education, income, and health.
First, you'll choose population variables to help you find areas where children are most at risk in Detroit.
- Verify that the country is set to United States.
- Locate and click the At Risk category. (If necessary, click the gray arrow on the right to scroll to the second page.)
- At the bottom of the Data Browser pane, click Show all At Risk Variables.
- Expand 2018 Key Demographic Indicators (Esri). Check the 2018 Children (Age <14) and 2018 Total Population (Esri) boxes.
Demographic data is updated periodically, so the available variables and values may differ from those specified in the lesson. If necessary, use the most recent data.
Next, you'll choose a variable for household income to locate areas of poverty.
- At the upper left of the Data Browser window, click the menu button to return to the main menu of categories.
- Locate and click the Income category. In the list of popular variables, check the 2018 Median Household Income (Esri) box.
- At the upper right of the window, confirm that the number indicates that three variables are selected. Click Apply.
The Data Browser window closes. The three variables that you chose are listed under the second parameter of the Enrich Layer tool. The third tool parameter defines areas around point and line features to enrich. You're enriching a polygon layer, so you don't need to define an area.
- Change the result layer name to Detroit Demographics and add your name or initials to make sure the name is unique within your organization.
New items created by analysis operations must have unique names within your ArcGIS organization. Once the layer has been created, you can rename it in your map.
- Confirm that Use current map extent is checked.
If this box is checked, only the census tract features that are visible in the current map extent will be enriched. The census tracts layer encompasses the entire United States, so if you unchecked this box, the analysis would take a long time. Analyzing the entire layer would also use a large number of credits. Credits are the currency for ArcGIS organizations and are consumed when using certain functions, including spatial analysis.
To view how many credits are required to perform this analysis, click Show Credits.
- Click Run Analysis.
When the operation finishes, the enriched census tracts layer is added to the map.
You'll rename the Detroit Demographics layer so it doesn't show your name or initials.
- In the Contents pane, point to the Detroit Demographics layer, click the More Options button, and choose Rename.
- Remove your name or initials and click OK.
The new layer looks similar to the original layer, but its features have new demographic data that you can use to change the layer's style and properties. You can see this new attribute information in the layer's table or default pop-up.
First, you'll remove the original USA Census Tract Areas layer, which is no longer needed.
- In the Contents pane, point to the USA Census Tract Areas layer, click the More Options button, and choose Remove.
The layer is removed from both the map and the Contents pane.
View the attribute table
Every layer in a map has an associated attribute table that contains information about the geographic features in the layer. You'll view the attribute table for the Detroit Demographics layer to better understand the data it contains.
- In the Contents pane, point to the Detroit Demographics layer and click the Show Table button.
You may have used more current demographic data in your data enrichment, and as a result, column names and attribute values may differ from those published in this lesson.
The layer's attribute table opens below the map. Each row in the table represents a feature (in this case, a census tract area). The columns, or fields, in the table provide different types of information about the census tract features. For example, the FIPS field contains a code that represents the state, county, and census tract identifier for each census tract feature, and the SQMI field provides the square mileage value for the census tract area.
Selecting a row in the table will select the corresponding feature on the map. You can use the Options menu to zoom to the selected feature and clear the selection.
- If necessary, use the scroll bar at the bottom of the table to scroll all the way to the right.
The demographic attributes that you added when you enriched the layer are listed as fields in the table. You'll apply a style to the layer using the values of the 2018 Median Household Income field.
- In the Contents pane, point to the Detroit Demographics layer and click the Hide Table button.
Style the layer
The Detroit Demographics layer is currently styled by location, showing all census tract boundaries in blue. You'll change the style of the layer to show and compare median household income.
- In the Contents pane, point to the Detroit Demographics layer and click the Change Style button.
The Change Style pane opens.
- For Choose an attribute to show, choose 2018 Median Household Income.
Based on the attribute you chose to map, several styles are offered. The nature of your data determines the default style suggestions. This is known as smart mapping. The recommended smart mapping style—in this case, Counts and Amounts (Color)—is marked with a blue check mark. The layer automatically updates on the map with a default color ramp that represents low to high median household income. Areas with the lowest median household income are drawn with a light color, while those with the highest values are drawn with a dark color. For now, you'll accept the default style.
- At the bottom of the Change Style pane, click Done.
By applying the recommended Counts and Amounts (Color) style to show median household income by census tract area on the map, you can see a clear pattern of low median household income in areas surrounding the Detroit city center. Later, you'll make adjustments to this style to help you identify areas in Detroit with high numbers of children under the age of 14.
Save the map
Now you'll save your map and assign it a title, tags, and a summary to make it easy to find and identify later.
- On the ribbon, click the Save button and click Save As.
- In the Title box, type Detroit Demographic Analysis.
- In the Tags box, type each of the following tags, pressing Enter after each one:
- child poverty
- demographic data
- income data
- census tracts
If you're signed in with an organizational account and your organization has set up content categories, you can assign your map to one or more categories to make it easier for others to find. To do so, click Assign Category and choose categories from the list. You can also use the Filter categories box to narrow the list of categories.
- In the Summary box, type This map shows demographic data in Detroit.
- Click Save Map.
The map is saved with the specified title, tags, and summary. (Once you've saved your map, it appears in your content, which you can access from the Home menu.)
In this lesson, you located the city of Detroit on a map and changed the basemap. You then added a layer of census tract areas from Living Atlas and enriched it with population and income data. Finally, you styled the layer to show median household income by census tract area and discovered a pattern of low median household income areas surrounding the Detroit city center. In the next lesson, you'll change the style of the Detroit Demographics layer to show both median household income and child population on the map. You'll also configure pop-ups to emphasize patterns in the data.