Improving business processes separately may entail limited success with respect to the overall performance of an organisation. Interfaces (i.e. dependencies) among business processes must be investigated and improved as well. Process maps are diagrams that can be used to illustrate business processes and their dependencies. Literature recommends a top-down process architecture approach, which implies first investigating interfaces and creating process maps before modelling business processes. In practice, organisations often first model business processes and then inspect their dependencies. Consequently, in this paper, a bottom-up approach is presented, which allows automatically generating process maps by importing process models expressed in terms of the Business Process Model and Notation 2.0. A proof-of-concept tool illustrates the approach. Two case studies and expert interviews attest our approach usefulness and ease of use.