In this working paper, we describe how to map research funding landscapes in order to support research funders in setting priorities. Based on data on scientific publications, a funding landscape highlights the research fields that are supported by different funders. The funding landscape described here has been created using data from the Dimensions database. It is presented using a freely available web-based tool that provides an interactive visualization of the landscape. We demonstrate the use of the tool through a case study in which we analyze funding of mental health research.