In recent years, two master plans have been created to guide Hanoi's development. The first was the Hanoi Master Plan 1990–2010, approved in April 1992. It was created out of collaboration between planners from Hanoi and the National Institute of Urban and Rural Planning in the Ministry of Construction. The plan's three main objectives were to create housing and a new commercial center in an area known as Nghĩa Đô, expand residential and industrial areas in the Gia Lâm District, and develop the three southern corridors linking Hanoi to Hà Đông and the Thanh Trì District. The end result of the land-use pattern was meant to resemble a five cornered star by 2010. In 1998, a revised version of the Hanoi Master plan was approved to be completed in 2020. It addressed the significant increase of population projections within Hanoi. Population densities and high rise buildings in the inner city were planned to be limited to protect the old parts of inner Hanoi. A rail transport system is planned to be built to expand public transport and link the Hanoi to surrounding areas. Projects such as airport upgrading, a golf course, and cultural villages have been approved for development by the government.