Architecture is both the process and the product of planning, designing, and constructing buildings or any other structures. Architectural works, in the material form of buildings, are often perceived as cultural symbols and as works of art. Historical civilizations are often identified with their surviving architectural achievements.
Planning is the process of thinking about the activities required to achieve a desired goal. It involves the creation and maintenance of a plan, such as psychological aspects that require conceptual skills. There are even a couple of tests to measure someone’s capability of planning well. As such, planning is a fundamental property of intelligent behavior. An important further meaning, often just called "planning" is the legal context of permitted building developments.
Urban planning is a technical and political process concerned with the development and design of land use in an urban environment, including air, water, and the infrastructure passing into and out of urban areas, such as transportation, communications, and distribution networks. Urban planning deals with physical layout of human settlements. The primary concern is the public welfare, which includes considerations of efficiency, sanitation, protection and use of the environment, as well as effects on social and economic activities. Urban planning is considered an interdisciplinary field that includes social, engineering and design sciences. It is closely related to the field of urban design and some urban planners provide designs for streets, parks, buildings and other urban areas. Urban planning is also referred to as urban and regional planning, regional planning, town planning, city planning, rural planning, urban development or some combination in various areas worldwide.
Architecture differs from a work of art, which can be displayed in different settings and the subject-matter, form and meaning will remain unchanged. The physicality of any built structure can be altered over time as additions and alterations are made. Moreover, a building or work of architecture can change its function as it meets the different demands of its occupants, although its exterior appearance may be unaltered. And its meaning may change depending on the nature of the context. This reveals some of the problems of interpreting historic architecture from a modern-day perspective as the physical changes and different cultural contexts transform the object.
Dana Arnold, Reading Architectural History (2002), Ch. 1 : Reading the past : What is architectural history?