Nummi Digitali: A pioneering multimodal platform for numismatic heritage.

This work presents a pioneering multimodal platform designed for the study, cataloging, and dissemination of numismatic heritage: "Nummi Digitali". This ecosystem enables a web-based structured recording of coin data according to Italian ministerial standards, international interoperability protocols, and Linked Open Data (LOD) principles. The back end facilitates rigorous cataloging and integration of high-resolution 2D imaging, 3D metric models, and archaeometric data-including non-invasive XRF analysis of alloy composition-while the front-end provides interactive access for researchers and the public. The platform's architecture supports multilevel user interaction, offering advanced analytical tools for specialists and accessible visualization for broader audiences. For the first time, a unified digital infrastructure connects traditional numismatic metadata with metrological, physical and chemical data, establishing a new paradigm in digital numismatics. Initially, the system was tested on a core collection of Greek, Punic, and Roman coins belonging to the "A. Salinas" Regional Archaeological Museum in Palermo (Italy), achieving significant outcomes in terms of scientific analysis, historical contextualization, and public engagement. Its scalable and standards-compliant design positions "Nummi Digitali" as a transformative model for interdisciplinary research and digital cultural heritage.