Space and place are fundamental to how people experience and interact with cultural heritage. Geographic Information Systems (GIS) provide heritage organisations with tools to manage spatial heritage data, and since the 2010s, efforts have been made to integrate GIS with the semantic web (web GIS). However, the adoption of web GIS by cultural heritage organisations remains limited due to challenges such as inconsistencies in spatial metadata documentation, a lack of granular gazetteers, and the need for sustainable spatial data infrastructure. This article examines these challenges through Ghent Mapped, a project in Flanders, Belgium, that aggregates urban heritage records from seven Ghentian heritage organisations into a unified web GIS. By reviewing Flemish metadata standards and the documentation practices of partnering organisations, we identify key barriers to spatial data interoperability and propose best practices for managing and sharing spatial heritage metadata.