Landscape planning is a branch of landscape architecture. According to Erv Zube (1931–2002) landscape planning is defined as an activity concerned with developing landscaping amongst competing land uses while protecting natural processes and significant cultural and natural resources. Park systems and greenways of the type designed by Frederick Law Olmsted are key examples of landscape planning. Landscape designers tend to work for clients who wish to commission construction work. Landscape planners analyze broad issues as well as project characteristics which constrain design projects. Landscape planners may work on projects which are of broad geographical scope, concern many land uses or many clients or are implemented over a long period of time. As an example, the damage caused by unplanned mineral extraction was one of the early reasons for a public demand for landscape planning. In Europe Alberti wrote on the need for town squares for markets and specific implementations to make most use of the space. In North Europe this developed into the idea that residential squares should be planned around green spaces. The first space of this type was the Place des Vosges. Residential squares were also made in Britain and their planning developed into the idea of incorporating public open space (public parks within towns). Frederick Law Olmsted gave momentum to this idea with his proposal for a park systems in Boston - the famous Emerald Necklace. Patrick Abercrombie took up this idea and incorporated it in his great 1943-4 Open Space Plan for the County of London. An example of landscape planning in use is the plans of RWE in the wake of its mining operations and how they plan to use leftover detritus and soil in their re-cultivation efforts to restore the damaged ecosystems and landscapes created by open pit mines (e.g. Garzweiler surface mine). In the US In the United States, landscape architects provide landscape planning services focused on the natural environment along with urban planners. But, unlike Canada and Europe, the US does not have a national land use planning system. Frederick Law Olmsted and Ian McHarg are two influential American landscape architects that also worked as planners. McHarg's work on overlay landscape planning contributed to the development of GIS and to the foundation of ESRI by Jack Dangermond. Legislation The principles of landscape planning are now incorporated in various types of legislation and policy documents. In America, the National Environmental Policy Act was