Data Blending vs. Custom Geocoding
If you have geographic locations in your data that are not automatically geocoded in Tableau, there are two ways to plot them on a map view–data blending and custom geocoding. Both data blending and custom geocoding allow you to plot your own locations on a map. Data blending is easier to set up and you can work with data from any data source. Custom geocoding lets you add to existing roles, and create hierarchies. Custom geocoding can be easier to use once it is set up and imported.
This topic explains the difference between blending geographic information with another data source and importing custom geocoding data into Tableau.
The following is a quick comparison of data blending and custom geocoding.
| Capability | Data Blending | Custom Geocoding |
| Plot your own locations on a map view | Yes | Yes |
| Use any data | Yes | No, text files only |
| Add new geographic roles | No | Yes |
| Add to an existing geographic role | No | Yes |
| Create new geographic hierarchies | No | Yes |
| Can be reused for other workbooks | No | Yes |
Data Blending
Data blending is the easiest way to plot your data on a map view. Data blending works great if you are adding a single level of geographic information with a latitude and longitude. You can use any data source, unlike Custom geocoding where you can only use text files. You can share the geographic data source with other workbooks on Tableau Server. You can also speed up your map performance by creating an extract that contains only your geocoding data.
The following is a high-level procedure for blending geographic data. For a more detailed example, see Blend Geographic Data .
To blend geographic data
- Create a data source that defines your geographic data.
- In Tableau Desktop, connect to the original data you want to map, and then connect to the data source that defines your geographic data.
- Blend the two data sources together. For more information, see Blend Your Data(Link opens in a new window).
- Plot the data on a map view.
Custom Geocoding
Custom geocoding is a more flexible way to plot your data on a map. Custom geocoding is available for all workbooks on a computer once the custom geocoding data is imported. The custom geocoding data will be copied into any packaged workbook (.twbx) or published workbook that uses a custom geographic role. This will make the workbooks about 40 MB larger.
If you upgrade Tableau Desktop, you may need to refresh your custom geocoding to take advantage of any fixes made to the geocoding data in Tableau.
In custom geocoding, you can use additional columns to define larger geographic locations. For instance, if you are creating a set of US census tracts, you may need to define which US county they fall in. You can include additional columns to define larger geographic locations in the import file.
You can also use multiple files for multiple geographic roles that have a matching relationship, meaning they share larger geographic data, such as country or state/province. Once the custom geocoding data is imported, you will see additional geographic roles that can be assigned to your geographic data.
Finally, custom geocoding lets you add additional places to an existing geographic role, such as adding new cities to the city role. It also allows you to define a hierarchy of geographic roles that extends the built-in hierarchies (e.g. census tracts in counties) or defines a new hierarchy (e.g. sub-territories in territories).
For more information about custom geocoding, see Geocode Locations Tableau Does Not Recognize and Plot Them on a Map(Link opens in a new window).