The AD4GD project will provide interoperability support for the heterogeneous and increasingly growing set of data and services available in the various action areas addressed by the GD (e.g., climate, energy, industry, agriculture and biodiversity), contribute towards the creation of an EU GD data space. This document will focus on the semantic interoperability building blocks enabling different systems to exchange data with unambiguous meaning, and to enable an integrated data access for the execution of advanced data analytics, to support the pilots. These building blocks include the semantic data model (AD4GD information model), the method and tools for extracting, harmonising, and sharing data, complying with data privacy and security requirements, and the set of open and standardised APIs necessary to provide the core services of the AD4GD ecosystem, which are based on the AD4GD information model.