The ReSeed project develops tools and methods to support the works of heritage professionals and ultimately the heritage decision process. Gathering around a common table institutions, the project connects Engineers (IT and KM) and Social Scientists (historians, curators , heritage experts) in order to produce a heritage knowledge management and decision supporting tool. This poster will present the LOD aspects of the works of the ReSeed project since its beginning in November 2016 in order to structure data, information and knowledge about one of its case study : the astronomical observatory of the Pic du Midi. This 150 years old scientific station located at 1877m on the top of the Pyrenees in the southwest of France hosted and still hosts biological , meteorological, and of course astronomical experiments. Such a place where history of science and techniques meets a local social history within a national and international history of scientists and institutions offers a great opportunity to deal with complexity. This poster will focus on two aspects: 1) on a tension we had to resolve on the integrity (of the heritage, of the source documents, and maybe of our model) and 2) on our solutions to deal with complexity and hetero-geneity while trying to integrate data and information from geometrical sources as much as more textual sources. The project's work is driven by its case studies and although we hope to deliver a more general solution , some aspects remain largely improvable and may seem at the time tailored to our needs.