This paper investigates the use of data-driven and interpretative models to support urban and territorial planning, with a specific focus on tourism as a complex spatial system. It introduces STESY (Sustainable Tourism Ecosystem), a methodological framework that classifies and interprets tourism destinations based on georeferenced data, spatial relationships, and thematic value chains. The model defines Specialized Tourism Destination Areas (DAs) as functional territorial units identified through the spatial coherence of attractions, services, and accessibility, rather than through predefined administrative boundaries. Tourism is conceived as a non-linear, open system, where complexity arises from the interaction between demand, supply, and contextual dynamics. In this framework, specialization refers to the alignment of territorial elements with a specific tourism identity—such as cultural, nature-based, or gastronomic tourism—allowing for flexible and context-sensitive applications. The stakeholder community is traced from service providers directly linked to POIs, enabling targeted engagement strategies that reflect the real structure of the local tourism system. The case study of the Vulture area, based on cultural tourism, illustrates how the model can support destination planning by identifying spatial units that are both analytically robust and practically meaningful. Rather than replicating complex realities through advanced simulations or digital twins, STESY offers a lightweight and interpretable approach focused on relational data structures. It advocates for technology to serve planning goals through clear problem framing and scalable, purpose-driven models—emphasizing usability, governance relevance, and local knowledge integration.