The objective of the operation is to produce a diachronic and homogeneous multidimensional land use database on the territory of Hauts-de-France, based on the OCS2D (Soil Cover x Soil Use) benchmark defined for the years 2005 and 2015 in the North and Pas-de-Calais. The diachronic nature of this database will make it possible to converge the various data previously produced in Picardy and Nord-Pas de Calais towards a 2021 vintage common to the five departments of Hauts-de-France. The high development and planning challenges associated with land use data imply a project approach focused on building consensus between the various local and regional stakeholders.