On the roadmap to reach the climate targets, Europe is committed to increase offshore wind power generation substantially from today towards 2050. This raises the question, what infrastructure layout efficiently integrates offshore wind power into the transmission grid. It is commonly addressed via scenario based optimisation studies to benchmark arbitrarily defined grid topology layouts such as radial connections of wind farms to shore against multi terminal offshore hubs or hybrid interconnectors. This paper proposes a new workflow to improve the design and calibration of topology scenarios for offshore grid studies with help of an automated process in a geographical information system. Against the backdrop of the recently adopted maritime spatial plans by EU member states, a high-resolution and large scale search graph of the future offshore grid is created with a multi-criteria analysis. Complexity reduction techniques are proposed to simplify this graph for subsequent investment optimisation studies. It is found that respecting the geographic reality of the heavily managed sea space not only reduces uncertainty for future offshore projects for more accurate cost estimates and cable trajectories. The consideration of designation areas in the sea also consolidates future grid planning options into common paths of transmission which facilitates the identification of relevant scenarios for analysis. It can be shown, that the commonly chosen benchmark of an “all radial” connection of wind farms to shore is a questionable choice to which an alternative is provided. The strategic relevance of the existence of spatial planning and access to high-resolution data for an improved grid development is demonstrated at the example of Baltic and North Sea.