The perceived world is more like an onion than an apricot; more like a diamond than a layer cake. From every angle, one sees a different landscape pattern, none of which has any superior claim to "reality'. All are reflections and transparencies, hopes and fears. Each can be seen only with certain eyes, from certain viewpoints, in certain light conditions. Deterministic planning developed from military maps. Democratic planning requires different maps. The mole, the house-martin and the eel have views of the world that are invisible to us, as do children, old people and blind people. Each individual has a mental map and a system of navigation. Human societies contain many interest groups that need special maps and plans. Only selected data can be shown on a map, and there has to be a principle for making the selection. Normally, it will be a functional principle, relating to characteristics of the existing environment or to a proposed future environment. Planning-by-layers may turn out to be the greatest invention since design-by-drawing.
Should an organization wish to conserve the world's house-martin colonies, it will require a map. Should another organization wish to increase the world's eel stock, it will require maps of breeding routes and breeding grounds. If a water company wants to recharge the aquifers in which underground water is stored, it must know where porous soils and rocks are located. If I want to avoid speed control cameras and park my car in Central London, I will need special maps showing the location of camera positions and parking places. Old maps were produced for military purposes. Modern maps are no less purposive, but the purposes are different. A mole's map would not extend above ground level. A swallows's map would be of air currents and flying insects. An eel's map would show routes to and from the Sargasso Sea. The Society for the Protection of Birds may wish to prepare a City Bird Plan. The creation of new habitats will be a central feature of this plan. They are likely to be beside railway lines and sewage works, in public parks, schools and gardens, and on flat roofs. Cities have large numbers of flat roofs, which could have been planned as bird habitats.
Transport has long been a central aspect of planning. In some countries, like Switzerland, the various modes are fully integrated. In others, like Britain, there are many discontinuities. Integration requires plans for the component subsystems and for the links. If the components are to function effectively, they must have their own maps and their own design teams. If the links are to be effective, different groups of planners must sit together under democratic umbrellas. Otherwise, cities cannot have footpaths and cyclepaths leading to sheltered places with coffee, newspapers and good connections to rail stations, bus stations and airports. An Equestrian Society could make a convincing case for a Horse Transport Plan. A significant number of town dwellers own horses, which do not get enough exercise. There could be bridleways running through those linear green wedges that landscape architects have been planning since Olmsted's time. Most of them are underused. Commercial stables could be franchised to locate at the city centre ends of these wedges, near transport interchanges. A Pedestrians Association may contribute to an overall Pedestrian Plan. They are likely to argue for a continuous pedestrian surface in cities. The paved sidewalk was a mid-nineteenth century invention, which has been greatly overused.
Multimedia GIS should supply information to all the different groups and bodies that wish to make plans. Many of them will also be able to supply information and contribute to the central database. Political bodies can take decisions when there are conflicts of interest, but democratic societies have proved remarkably successful at accommodating individuals, provided they have the necessary information. If planning is to be reborn, planners need to focus their minds on GIS, structuralism and planning-by-layers.