Cosmic-ray muography uses high-energy particles for imaging applications that are produced by cosmic rays in particle showers in the Earth's atmosphere. This technology has developed rapidly over the last 15 years, and it is currently branching out into many different applications and moving from academic research to commercial application. As in any new sub-field of research and technology, the nomenclature of the field itself is still developing and has not settled yet as new aspects of the field are appearing and with them the terms to describe them. This overview of the field of muography is not going to focus on the physics, on the reconstruction algorithms or on the involved detector technology. Detailed papers on these aspects are included in this issue of Philosophical Transactions A and I will refer to them. Instead, I will give an overview of the field as it is now, in 2018, and try to give an idea of the future directions in this field as I see them. This article is part of the Theo Murphy meeting issue ‘Cosmic-ray muography’.