I was reading an article few days ago on Australian population and was inspired to create a visualisation in tableau  using latest tableau features i.e. buffer calculation to demonstrate Australian population stats in a different way.

Tableau introduced three spatial calculations in 2019 i.e. Makepoint and Makeline (in 2019.2) and then Distance (in 2019.3). Tableau has recently introduced another spatial calculation in 2020.1 i.e. Buffer calculation. it allows you to visualise the distance around a point location. It returns a buffer of a given distance around a point and it looks like a circle.

Data

I have downloaded the data from ABS website. 

Calculated Fields

Buffer

This will create a buffer distance around a point  and in this case we are plotting a point using parameter Latitude and Longitude which is dynamically changed by clicking on a map. I have used parameter actions to do that.

BUFFER(MAKEPOINT([Parameters].[Lat],[Lon]),[Radius in KM],’km’)

Parameter : Latitude
Parameter: Latitude End
Parameter: Longitude
Parameter: Longitude End

Worksheet

  • Change the Mark Type to Map
  • Drag Longitude to column shelf
  • Drag Latitude to row shelf
  • Drag LGA Name to Details shelf
  • Drag Centroid to details shelf
We will create multiple layers to create  the desired affect.
First Layer is used for background map
Second Layer is used for Pointing the lat and long on the map
Third layer is used for marks and the fourth layer is used for buffer around a point.
After doing a bit of formatting it will look something like below and this dashboard can be accessed by clicking here