Land cover classifications are recognised to be a fundamental source of data to characterise Earth surface and to support change detection analyses. Land cover maps have been produced from different sources as a result of massive time-series image processing. This paper proposes a REST API that allows for computing the percentage of Land Cover classes of a geographic area using such a map. The computed data is then represented as RDF triples based on an ontology dedicated to this kind of data together with their temporal and spatial dimensions. We illustrate the use of the API to study the evolution of Land Cover on a specific geographical area.