What are spatial functions in Tableau?
Spatial functions allow you to perform advanced spatial analysis and combine spatial files with data in other formats like text files or spreadsheets. In this blog, I’ll show you how to use the spatial functions in Tableau to create lines and points on the map based on airport data.
Sample
We are going to create the below chart. The data is available here.
Figure 1. Sample
Steps to re-establish the chart
a) Create Start Point
Create Start Points based on the latitude and longitude of the origin airport.
Figure 2. Start Point statement
b) Select the Sydney Airport
Double-click the <Start Point> to show all the origin airports on the map.
Figure 3. Show Start Points
Right-click the <Name Origin Airport> and select Show Filter.
Click the top-right drop-down Botton of the filter and select the Single Value (list).
Type ‘Sydney’ to find the Sydney Kingsford Airport.
Figure 4. Locate Sydney Kingsford Airport
c) Create End Point and Show them
Create End Points based on the latitude and longitude of the destination airport.
Figure 5. End Point Statement
Drag the <End Point> to the Marks Layer button.
Figure 6. Add End Point to Marks Layer
Then we can see the Sydney Kingsford Airport Point and its corresponding Destination Airport Point.
Figure 7. Show End Points
d) Make Lines between the Start Point and End Point
Create lines.
Figure 8. Lines Statement
Drag the <Journey> to the Marks Layer button.
Then we can see the routes.
Figure 9. Show Lines
e) Create a Buffer
First, create a parameter of radius.
Figure 10. Radius Parameter
Create the Buffer based on the origin airport.
Figure 11. Buffer Statement
Drag the <Buffer> to the Marks Layer button.
Figure 12. Show Buffer
f) Color the routes within the buffer
Create the adjustment calculated field.
Figure 13. Within Buffer Statement
Put it on Journey’s Color Marks card.
Figure 14. Color the routes within the buffer
g) Show details
When you hover over the lines and destination airports, you always select the whole lines & end points.
Figure 15. Hover on the lines
Figure 16. Hover on the End Points
To show all the details, we should put <Name Destination Airport> to Journey and End Point’s Detail of the Marks card.
GIF 1. Show details of lines & End Points
h) Format the Start Point and End Point
We can format the start and end points to distinguish the origin and destination airport.
Change the Start Point to Circle in Marks Card. Increase the Size and edit the Color.
Change the End Point to Shape in Marks Card. Select Star Shape and edit the Color.
Then we can get the final chart.
Figure 17. Final Chart
If there are any problems, please feel free to point them out. Besides, you can reach out to me on LinkedIn. I will try my best to answer your questions about Tableau or Alteryx.