PostGIS is an open source software program that adds support for geographic objects to the PostgreSQL object-relational database.
License: Open Source
PostGIS is an open-source spatial database extender for PostgreSQL, known for its flexibility and performance with large datasets, but it may present a steeper learning curve for new users. In contrast, ArcGIS offers a user-friendly interface and comprehensive tools, making it ideal for users who require extensive GIS capabilities, albeit at a higher cost.