This census help guide will take you step by step through joining data to boundary shapefiles. Once you have downloaded Census or National Household Survey (NHS) data in .dbf format, you can join it to a shapefile and map it.
**For a slightly different workflow using census data in Excel format, watch this University of Toronto Mississauga video.
If you have any issues with this process or further questions, please don't hesitate to contact us!
Step 1: Figure out the census geography you want to map
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.: CD code for census divisions) or 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.
Step 2: Get the correct shapefile for your data
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 2016 and many previous census years, find links from this page.
- 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.
Step 3: Add both the shapefile and data file to ArcMap
Using the Add Data button , add the shapefile and DBF data file to ArcMap. The Table of Contents window in ArcMap should include both the shapefile and the DBF file.
Step 4: Join the data to the shapefile
The exciting part!
- 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 gfed000b11a_e).
- Click Joins and Relates... > Join...
- In the resulting window, input the following parameters:
- "Join attributes from a table" in the top drop-down list
- The field to base the join on will be FEDUID in this example. If you have census districts, it'll be CDUID. Census tracts, CTUID. And so on. This table includes abbreviations.
- Select the DBF data table you added in the previous step.
- You'll need to refer to the header file for the DBF table to find out which column is appropriate. It is often COL0.
- Click Validate Join to confirm that the parameters are correct.
- Click OK.
- It looks like nothing happened: that's normal. 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.
Step 5: Export the shapefile to make the join permanent
- Right-click the title of your boundary shapefile in the Table of Contents.
- Select Data > Export Data...
- Save the shapefile in the location of your choice.
- Select Yes when asked if you'd like to add the layer to the map.
BONUS Step 6: Symbolizing
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:
- Right-click on your newly saved shapefile and click Properties... at the bottom of the menu.
- Click the Symbology tab.
- Click Quantities > Graduated Colors in the left window.
- Under Fields: Value, select the column you'd like to base the symbology on (in the example here, it's COL4). You may need to refer back to the header file to find out which column you'd like to symbolize.
- 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.
- Select a color ramp you like. A light-to-dark ramp of the same colour is recommended for this type of map.
- Click OK.