Within large construction companies GIS is widely used to store, analyse and visualise spatial data. GIS is just one of the components of an information infrastructure and has to be an integral part that can provide data and information to other departments and subcontractors as well. Van Oord as a marine contractor deals with spatial data on a daily basis. Existing disciplines like the design team and Survey team already have their way of dealing with spatial data to fulfil their task. What is it that the organisation needs additionally to work with GIS? Van Oord has chosen to use FOSS4g software as a GIS backbone. This choice has its benefits but also poses challenges. Most competitors in the business use proprietary software. Clients do not necessarily follow standards and the IT department has to support our requirements. We are very proud of our GIS backbone and definitely see the benefits of using FOSS4G. Come and listen to the solution we have chosen; the changes we make in the business and challenges we face.