Planning requires knowledge, understanding and visions The theme of this chapter is that landscape planners should be guided by three types of consideration: - knowledge of the past - understanding of the present - visions of the future Development planners and designers should consider the environmental impact of development projects on past, present and future. This may identify ideals and planning objectives which are in conflict. Consider a field on the periphery of a major city. The landowner wishes to construct a factory on the land. The Habitat Plan calls for the field to be restored to its former condition, as a wet oakwood. The Recreation Plan calls for public access. The Rural Scenery plan calls for its agricultural character to be conserved. The Urban Scenery plan calls for the land to be built upon, as an extension to a citywide development axis. Economics and politics will guide the debate. Though imaginative design can help, theories of context are also required. They are the subject of the next chapter.