Based on Polygon for Tableau module developed by Alteryx Sales Engineering Team
Modify your polygon files for use in Tableau visualizations. This process will read in a spatial file format including a polygon field, and decompose the polygon into its individual spatial components in a format that is friendly for tableau to read in and consume. Please see the link below for more information on how to read these files into Tableau.
Consider generalizing polygons for complex spatial objects to reduce the number of component points and decrease file size.
Create polygon maps in tableau