Introduction
Spatial parameters in Tableau represent a significant advancement in the platform's capability to handle geospatial data. Introduced in the 2024.3 release, spatial parameters allow users to create dynamic and interactive visualizations that incorporate geographic elements such as points, lines, and polygons.
This article extends the previous discussion on INTERSECTS function by demonstrating how to use spatial parameters to determine overlapping spatial objects in a dynamic way. Using the same dataset used in the previous article on INTERSECTS, I would like to show facilities that are within 1,000 feet of the three VCT centres namely ‘Carolina for Kibera’, ‘Kicoshep Centre’, and ‘Mtaani VCT’ using a spatial parameter.
Create a Spatial Parameter
Create a spatial parameter as shown below.
Note: The data type selected on the parameter is “spatial”.
On the allowable values, I have listed the well-known text (WKT) values for the three VCT centers.
Note: You can create WKT values in Tableau using the Latitude and Longitude fields as shown below.
POINT( [Longitude] [Latitude])
For example, to create the WKT value for “Mtaani VCT” I have used the following POINT(36.7985247 -1.3133393) and assigned the alias as Mtaani VCT.
Create a View Mapping all Facilities in the Data
Using MAKEPOINT function create a calculation to map all the facilities in the dataset.
Drag the calculation to the detail shelf.
Add more details by dragging the facility name to the detail shelf.
Add facility type to color.
Create a buffer calculation to show facilities that are within 1,000 feet of the facility selected on the parameter.
Adding the buffer calculation to the Marks Layer we have.
Notice that changing the selection on the parameter recomputes the boundary based on the selected facility.
Add Zooming Effect for Better Focus
You can add zooming effect to enable users focus only on facilities that are overlapping with the buffer using the following calculation.
Adding the above calculation to the filter shelf and selecting TRUE we’ve.
The above gives a more focused view of the area of interest – allowing users to focus only on facilities within 1,000 feet of “Kicoshep Centre” (the facility currently selected on the parameter).
Conclusion
The introduction of spatial parameters in Tableau marks a pivotal enhancement for users working with geospatial data. By allowing for dynamic interactions and advanced calculations involving geographic elements, Tableau empowers users to create richer insights and more engaging visualizations. As organizations increasingly rely on location-based data for decision-making, mastering spatial parameters will be crucial for analysts aiming to leverage Tableau's full potential in geospatial analytics.
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