Nature has always been a subject of art, from the first cave paintings to twentieth-century landscape photography. I wanted to use the landscape as an artist in new ways. First I started making work outside using natural materials like grass and water, and this led to the idea of making a sculpture by walking. This was a straight line in a grass field, which was also my own path, going nowhere. In the subsequent early map works, recording very simple but precise walks on Exmoor and Dartmoor, my intention was to make a new art which was also a new way of walking: walking as art. Each walk followed my own unique, formal route, for an original reason, which was different from other categories of walking, like travelling. Each walk, though not by definition conceptual, realised a particular idea. Thus walking – as art – provided a simple way for me to explore relationships between time, distance, geography and measurement. These walks are recorded in my work in the most appropriate way for each different idea: a photograph, a map, or a text work. All these forms feed the imagination.