In the search for the ideal spatial data infrastructure a common ground has been established for the development of open spatial data infrastructures. Starting from confidential, highly restricted data with use limited to particular public sector users, SDIs across Europe have developed towards a wider focus, civil society oriented infrastructure enabling a multitude of users to access, share, use and re-use datasets and services from a wide variety of domains both nationally and internationally. Especially in recent years, several countries and public administrations started to make a shift towards the establishment of an open spatial data infrastructures (SDIs), in which also businesses, citizens and non-governmental actors were considered as key stake-holders of the infrastructure. In this workshop, the concept of Open SDI/INSPIRE was introduced to describe characterize the development and implementation of more open spatial data infrastructures. During the workshop a first prototype of the ‘Map of Open SDI in Europe’ was presented, showing the results of a first exploration of the openness of NSDI/INSPIRE implementation in Europe. The ‘Map of Open SDI in Europe’, a project of the Knowledge Centre Open Data of Delft University of Technology, is developed to provide SDI decision makers, practitioners and researchers with a more comprehensive understanding of the openness of spatial data infrastructures in Europe. The Map covers three key dimensions of Open SDIs: the readiness, the data availability and accessibility, the use of spatial data and the associated benefits. The map provides an overview of the actions and initiatives taken in different Member States to open their SDI to stakeholders outside the public sector. A workshop was organised at the INSPIRE Conference 2017 to demonstrate the map to the public and get input on how to further it improve it. During the workshop, several brainstorm sessions were organized on each of the key dimensions of Open SDIs. The main aim of these brainstorm sessions was to collect ideas on how to measure and assess each of the four dimensions and explore good practices that could be added to the Map. This report provides a summary of the workshop and the main results. This workshop report was prepared under the project ‘Effective Governance of Open Spatial Data’ (E-GOS). This project has received funding from the European Union’s Horizon 2020 research and innovation programme under the Marie Sklodowska-Curie grant agreement No 706999.OLD Geo-information and Land Developmen