Most construction project designs are executed by engineers and architects using CAD programs. Environmental and landscape planners use GIS to assess the environmental impacts of the construction projects and their visual, ecological and functional integration in the landscape. To fulfil the requirements throughout the entire lifecycle of a construction project, CAD and BIM data must be converted to GIS formats and combined with GIS datasets, so that the necessary environmental analyses can be performed. Using the example of the Autobahn A99 expansion in Munich, this paper describes a workflow for data conversion and integration of CAD, BIM and GIS in environmental and landscape planning.