Census of Canada: Joining Census Data to Boundary Shapefiles in ArcGIS Pro

Since you already downloaded the data (if not, please do so!), you probably already know the geography you're looking at (e.g.: census tract, dissemination area, census metropolitan area). If not, it's easy to find: just look at the header file with your data (usually a .txt file) and it will give you the names of the columns. One of the first columns will be the geography code (e.g.: FED code for federal electoral districts) and the title in the header file itself may say which geography it is for.

If you see an abbreviation (e.g.: CD, CMA, CT) that you are unfamiliar with, consult the table on this page for clarification.

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Once you know the census geography you are going to map, you need the corresponding boundary shapefile.

• If you are only looking at Ottawa-Gatineau, find the shapefiles here (includes historic years back to 1951).
• For Canada-wide boundary files from 2021 and many previous census years, find links from this page.
  • Make sure to use the shapefile for the same census year as the data you're using!
  • The Statistics Canada links provided are generally more straightforward. Select "Cartographic Boundary File."

You may find it helpful to save the shapefile in a project folder with the data you wish to map.

Using the Add Data button that's found in the Map ribbon in the Layer section, add the shapefile (make sure it's unzipped!) and DBF data file to your map. The Contents pane in ArcGIS Pro should include both the shapefile and the DBF file, and the DBF file will show up under the Standalone Tables heading.

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It's always a good idea to get to know your data a bit:

1. Right-click on both the shapefile and the DBF data file and open the attribute tables
2. Have a look at the two attribute tables.
   • There should be a field in the shapefile with "UID" in the field name, such as FEDUID (for federal electoral districts) or CTUID (for census tracts)
   • This is also when you want to have the DBF header file nearby, because the field headers are COL0, COL1, etc., and we'll need to find the GEO UID field
3. Make sure you know what the headers are for the two UID fields because you'll need them in the next step!

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The exciting part!

1. Right-click the title of your boundary shapefile (in this example, the Federal Electoral Districts are being used so the filename is the clear-as-mud lfed000b16a_e).
2. Click Joins and Relates... > Add Join
3. In the resulting window, input the following parameters:
   • Input Table: the boundary shapefile
   • Input Join Field: the __UID field, FEDUID in this example. If you have census districts, it'll be CDUID. Census tracts, CTUID. And so on. This table includes abbreviations.
   • Join Table: select the DBF data table
   • Join Table Field: this is the GEOUID field, which you'll need the DBF header file for. It is often COL0.
   • Keep All Target Features should be checked off
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4. Click Validate Join to confirm that the parameters are correct. This may take a moment.
5. Click OK.
6. It looks like nothing happened: that's normal. If the boundary shapefile attribute table isn't open already, right-click the title of the boundary shapefile and select Open Attribute Table to see the data from the DBF file added to attribute table. This is temporary so you'll need to export the shapefile to save it permanently.

If you open the attribute table and there are many empty rows, go back and double-check that you are joining the right fields.

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1. Right-click the title of your boundary shapefile in the Table of Contents.
2. Select Data > Export Features
3. Browse to save the shapefile in the location of your choice and give it a helpful name!
4. Click the Fields drop-down
   • In the list of fields, click on COL0, then the Properties tab on the right
   • Open the header file and input helpful field names to replace COL0, COL1, etc. by typing in the Field Name textbox
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     • Try to keep the new field names fairly short if you can
   • Click OK
5. The new shapefile/feature class should have the new field names in the attribute table, which will make it easier to know which column is which.

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The fun part!

The shapefile is a polygon (area) shapefile, so you can symbolize based on the numeric data that is now permanently joined to your new shapefile. The example being used in this help guide is population density by square kilometer in each Federal Electoral District, so to symbolize based on similar data you can use the following process to create a choropleth map:

1. Right-click on your newly saved shapefile and click Symbology
2. A Symbology pane should open on the right side of the ArcGIS Pro screen
3. In the drop-down under Primary Symbology, click Graduated Colors
4. In the Field drop-down, select the column you'd like to base the symbology on (in the example here, it's PopDensity). You may need to refer back to the header file to find out which column you'd like to symbolize if you didn't change the field names in Step 5.
5. Under Classification, select as many breaks as you'd like. The default is 5 but you may want more. You may also want to change the classification to Equal Interval instead of Natural Jenks. You can also manually adjust the numbers if the intervals you get are not to your liking.
6. Select a color ramp you like. A light-to-dark ramp of the same colour is recommended for this type of map.
7. Click OK.

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