How to Join Data Tables to Data Layers in ArcMap 10

Uploaded by UTMLibrary on 15.07.2011

Joining an Excel data table to an ArcMap data layer enables you to map Thematic variables.
Joining an Excel data table to an ArcMap data layer enables you to map thematic variables.
In this case, we will join an age and sex data table of the Greater Toronto Region
to a map of Mississauga by Census Tract.
You must first edit your table in Excel.
In ArcMap, have your data files opened. You must now ensure that there is a common column
between the data layers' attribute table and your Excel table for the join.
In this case, we are joining by Census Tract identification numbers.
Right click on the Mississauga layer and select 'Open Attribute Table'.
Open the excel table by right-clicking and selecting 'Open'.
The common column for joining between both columns is CTUID, which is the Census Tract identification number.
Right-click on the excel table and click 'Properties'.
Under the 'Fields' Tab, click on the joining column and check the Data Type.
In this case, it is 'Double'. Click 'Ok'.
Repeat this for the attribute table of the data layer. The joining column is a text type,
which should join. However, in most cases, the Data type is a 'String'
which will not allow you to join it with your Excel column.
To fix this, we must create a new joining column in Mississauga's attribute table.
Once opened, click on the 'Table Options' icon on the top left, and 'Add Field...'.
Provide a similar name, such as CTUID2. Under type, select 'Double'. Click 'Ok'.
The new column has been added.
To add data to it, right click on the new column header, and select 'Field Calculator'.
Under 'Fields', double click on CTUID so that the equation reads 'CTUID2=CTUID'. Click 'Ok'.
The new field contains the same data as the CTUID field.
Now you are able to join.
Right click on Mississauga, select 'Joins and Relates', 'Join'.
Ensure that 'Join attributes from a table' is selected.
By step one, locate the joining field from the data layer, which is CTUID2.
By step two, ensure that the excel sheet is selected.
By step three, locate the CTUID joining column from your excel file.
Under 'Join Options', select 'Keep only matching records' to eliminate data beyond Mississauga. Click 'Ok'.
If you open the attribute table of the data layer again, you will see the inserted excel table columns.
For further instruction in ArcMap, please visit our video archives.