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ArcGIS Tutorials

ArcGIS Pro: Quantitative Mapping

ArcGIS Pro: Quantitative Mapping

This self-paced tutorial includes all necessary steps to create a thematic map using numeric census tract data - from data acquisition; Excel file formatting; preparing a boundary shapefile; to the final product of designing a choropleth map using ArcGIS Pro software. If you have questions or need assistance, email maplib@brocku.ca for help.

Tutorial

A step-by-step tutorial to introduce curious people to ArcGIS Online:

  1. Downloading Census data
  2. Preparing the Excel file
  3. Download Census Tract Boundary Files
  4. Adding Data
  5. Projections
  6. Preparing the Attributes
  7. Joining by Attributes
  8. Choropleth Mapping
  9. Layout
  10. Printing

 

1. Downloading Census Data

The Canadian Census Analyser (CHASS) is a website hosted by the University of Toronto that allows for easy selection and download of Canadian Census data variables. You must be affiliated with Brock University to access this database.

 

  1. Navigate to Brock Library's database search https://researchguides.library.brocku.ca/az/databases
  2. Use the keyword search and enter "Canadian Census"

Canadian Census Analyser search result listing

  1. Click the title to enter the database. If you are off campus, sign in using your Brock username and password.
  2. Under Starting Points > Census Profile Tables > by Census Geography, select Census Tract
  3. Select 2016
  4. Step 1: Specify Census Geography for retrieval
    1. Under the heading Locate census geography, click the checkbox beside the letter 's' and uncheck 'a'
    2. Check the box beside St. Catharines - Niagara (Ont.)
  5. Step 2: Specify Census Variables for retrieval
    1. Select the tab for "Housing" then select the following:
      1. Average monthly shelter costs for rented dwellings ($)(v3950) (Scroll all the way to the bottom of the list)
    2. Select the tab for "Education" then select the following:
      1. Total - Highest certificate, diploma or degree for the population aged 15 years and over in private households - 25% sample data (v4920) (This is the first variable in the list)
      2. University certificate, diploma or degree at bachelor level or above (v4929)

Selection of census variables listed

  1. Scroll down to Select the output format:
    1. Select MS Excel ready
  2. Click Submit Query. The CSV is automatically downloaded to your My Downloads folder.
  3. Run File Explorer (THIS PC) and copy/paste the CSV to a more appropriate storage location (i.e. OneDrive or a USB).
  4. Open the file (default name is census.csv) in MS Excel.

Excel file showing the downloaded variables

 

 

2. Preparing the Excel File

The Excel file must be cleaned up before it can be used in ArcGIS. Take a moment to study the column descriptions and data.

  1. Using the descriptions for each "COL" (column), enter a truncated field name in the cells just above the data (i.e. using row 9 in the screenshot above). Field names MUST begin with a letter, contain only letters/numbers/underscore characters and be limited to 64 characters long. DO NOT INCLUDE SPACES OR SPECIAL CHARACTERS!

  1. Select rows 1 through 8 (in this example) and right-click > Delete.
  2. Go to File > Save as and save the Excel Workbook to your project folder. ArcGIS Pro works with Excel files in various formats (.xlsx or .csv).
  3. Close Excel completely before continuing.

 

3. Downloading Census Tract Boundary Files

  1. Using Google Chrome (recommended), navigate to Scholars GeoPortal > Cartographic Boundary files https://geo.scholarsportal.info/#r/details/_uri@=1339490473
  2. Click Add button and choose the Census Tracts layer to Add.
  3. Zoom to Niagara.
  4. Click the Download tab then select Download by area of interest > Select a pre-defined area > Census Division (CD) then click anywhere over Niagara.

NOTE: There are no census tracts for West Lincoln.

Scholars Geoportal interface with census division selected

  1. Click Download.
  2. Under My download list, click the ZIP file to download it.
  3. Using File Explorer (THIS PC), navigate to My Downloads and copy/paste the zipped file to your preferred storage location (i.e. OneDrive or USB).
  4. Right-click the zip file and select Extract All to unzip the file.
  5. Close File Explorer.

 

4. ArcGIS Pro - Adding Data

  1. Run ArcGIS Pro (sign in using your Brock username/password as described in this tutorial).
  2. Create a New Project > Map
  3. Provide a name for the project and browse to an appropriate storage location (OneDrive or USB).
  4. Click OK.

ArcGIS Pro creates a project file that includes all maps, tools, styles, etc. associated with your mapping project.

  1. If necessary, click the View tab and select the Catalog pane to view the associated components.

Catalog pane in ArcGIS Pro

  1. Right-click Folders and select Add Folder Connection.
  2. Browse to the folder holding the unzipped shapefile of census tracts and the Excel file. NOTE: This is just a FOLDER shortcut.
  3. Expand Folders to see the newly created shortcut.

Expanded folder connections pane

  1. From the Map tab at the top, click Add Data. Do not click the little down arrow.
  2. Under Project, click folders to see the shortcut created in the step above.
  3. Double-click the folder shortcut and navigate to the Excel workbook.
  4. Double-click the workbook and select the census sheet.
  5. Click OK. The table appears in the Contents listing to the left of the map under the heading Standalone tables.

Contents pane in ArcGIS Pro

  1. Click Add Data again and select the unzipped shapefile. NOTE: If you can't see the shapefile, either refresh the window or make sure you've gone through the unzipping process described in Section 3 above.

map view showing the added shapefile

The map has zoomed to the extent of the shapefile, seen above. The default projection makes the map look tilted. We will set the coordinate system for the map frame next.

5. Projections

  1. From the Contents panel on the left, under Drawing Order, double-click Map.
  2. Click Coordinate Systems.
  3. In the Search box, enter "UTM". Hit Enter on the keyboard.
  4. Double-click Projected coordinate system.
  5. Double-click UTM then North America, then NAD 1983.
  6. Scroll down and select NAD 1983 UTM Zone 17N. 
  7. Click OK.

selection box for projection information

 

Projected map of census tracts

 

 

6. Preparing the Attributes

This section involves joining the census data table to the census tract boundary file based on a common column.

  1. In the Contents pane, right-click the census tract boundary layer (i.e. DLI_2016_Census_CBF_Eng_Nat_ct) and click Attribute Table to open the associated table.
  2. Each census tract is linked with a row of attributes. Notice the column CTUID. This column matches a column of data we downloaded with the census data.

Census tract attribute table with CTUID field highlighted

  1. In the Contents pane, right-click the standalone table 'census$' and click Open. The first column represents CTUID as well. We will perform a JOIN based on CTUID (census tract unique identifier). But first we need to create a new field that will populate the CTUID in the same DATA FORMAT as the census data.
  2. In the Table view, click the table header named DLI_2016_Census_CBF_Eng_Nat_ct
  3. Just below the table header are options for working with the table. Click the Add button to add a new field. The view switches to the Table Fields view.
  4. Enter a new field named "CT_UID". This name must be unique from the other field names.
  5. Double-click the Data Type cell and select Double.
  6. Under Number Format click the ellipsis button and choose category Numeric with 2 decimal places. Click OK.
  7. From the Fields tab at the top of the screen, click Save.
  8. Re-open the attribute table for the census tract layer. Notice the new field added to the far right of the table.

Attribute table with the newly created field outlined in red

  1. Right-click the new field header and select Calculate Field.
  2. The goal is to populate the new field with the appropriately formatted CT UID. From the Fields section, double-click CTUID. The expression is automatically populated as follows:

Calculate field dialogue box with expression outlined in red

  1. Click Apply. The CT_UID attribute field now matches the data type of the census data CT UID.

 

7. Joining by Attributes

In this section we will combine the census variable data with the attributes of the census tract shapefile attribute table based on the common field defined above.

  1. In the Contents pane, right-click the census tract boundary layer and select Joins & Relates then select Add Join. The Add Join tool pane is activated.
  2. In this example, the software intuitively matches the fields from the shapefile and census attributes. Confirm the Input Field reflects the new field added in the previous section (CT_UID).

Add join dialogue box

  1. Click OK to apply the join.
  2. To view the result, activate the table associated with the census data. It should be docked below the map view.
  3. Scroll to the right to see the joined attributes.

Attribute table of data with joined fields highlighted by a red box

 

8. Choropleth Mapping

A choropleth map applies a graduated colour scheme based on certain attributes. The first map we will make reflects the Average Rent variable. You may notice that the census tracts for the Grimsby area are no longer included. This is because the census data was downloaded based on the Census Metropolitan Area which differs from the Census Division. Contact maplib@brocku.ca for more information.

  1. Click the census tract boundary layer to activate it.
  2. Click the Feature Layer tab at the top of the screen.
  3. Click the Symbology dropdown and select Graduated Colors.
  4. Beside Field, select AvgRent from the dropdown list.
  5. A default colour scheme is applied to the map where darker colours represent higher values.

Feature Layer > Symbology options list with graduated symbols selected

 

Choropleth map showing average rent by graduated colours.

  1. Save your map by clicking the third button at the very top left of the ArcGIS Pro window save button panel.

A lot of census data must be represented as a percentage. This is known as 'normalization'. For example, the variable we downloaded for highest level of schooling (Bachelor Degree or Higher) must be mapped as a percentage of the population 15 years of age or older. Follow these steps to normalize a value:

  1. Right-click the census tract layer and select copy.
  2. In the Contents panel, below Drawing Order, right-click the word Map and select Paste. You now have 2 layers representing the census data.
  3. Click one of the census tract layers then click the layer name a second time (THIS IS NOT A DOUBLE CLICK). Enter a new descriptive name such as "Average Rent". Then turn the layer off by unchecking the visibility box. 

Average Rent symbology

  1. Select the copied layer to activate it (make sure it's the visible one).
  2. From the Symbology pane on the right, change the field option to BachDeg_Higher (your field name may differ).
  3. Beside Normalization, select the field representing Pop15ov (Population 15 and over).
  4. Select a new colour scheme and see the map reflect your changes.

Symbology pane showing options for mapping education using normalization

To enhance our understanding of the map, we will adjust the legend values to reflect percentages (by default the number represents a fraction).

  1. From the Symbology pane, click the advanced symbol options button tool button with advanced symbol
  2. Under Format Labels, beside Category, select Percentage.
  3. Under Percentage, select Number represents a fraction. Adjust it to show as a percentage.
  4. Change the number of decimal places to 2.

Advanced symbology options window

  1. Rename the layer associated with the new symbology.

Symbology, labels, layer name

  1. Save your map.

 

9. Layout

After creating the choropleth maps, it is a good idea to create a layout that includes the map, a legend, scalebar and North arrow.

  1. From the Insert tab, select New Layout > Landscape > Letter

Essentially, a layout is a virtual piece of paper that you will add cartographic elements to for your map layout. In order to maintain a margin, we will add guides.

  1. Right-click the ruler at the top of the layout and select Add Multiple Guides.
  2. From the Orientation options, click Both.
  3. From the Placement options, select Offset from Edge.
  4. From the Margin options, enter 0.5 to give the page a half inch margin.
  5. Click OK.

Add guides window with options

  1. From the Insert tab, in the Map Frames group, select Map Frame and select the map frame representing your choropleth map.

Map frame insert options

  1. Draw a box on the layout to define the size of the map within the margins.

resulting map frame on the layout

  1. To enlarge the map display (zoom) we have to activate the map frame. Right-click the map frame and select Activate. You can now zoom and pan.
  2. When you are satisfied with the extent, click the red X at the top right of the map view.
  3. To add other map elements, go to the Map Surrounds group from the Insert tab and add a North Arrow, Scale bar and Legend.
  4. To add a title or other text, click the Text tool in the Graphics and Text group on the Insert tab. Click on the layout and start typing your text. 
  5. With an element selected you will see the options associated with the element in the pane to the right.
  6. To resize or move an element, click on the element to select it, then use the handles to resize or grab the element in the centre to drag and drop it to a new location.
  7. Save your map!
  8. To share your map with others, click the Share tab then click Export Layout. You can choose from a variety of file formats and a variety of settings. 

Layout options page

Final Layout of the choropleth map with all map elements added

10. Printing

You can print from the exported file or you can print directly from the Layout view.

  1. From the Share tab, click Print Layout.