Towards a strategy for control of suburban informal buildings through automatic change detection

The problem of informal settlements is of significant importance and has similar causes worldwide. In Greece, such buildings are relatively well built and number nearly 1,000,000 across the country. This social and economic issue requires a combined approach. In this paper, a proposed solution to this problem is developed at a technical and administrative level, taking into consideration the criteria of least possible cost and maximum benefit from usage of modern technology. The basic idea is the development of a system that allows for periodic, automatic monitoring and detection of new buildings. With additional field control applied only to specific locations, immediate detection of informal construction projects prior to completion is enabled, at which time measures to halt their development can be more easily taken. The suggested procedure is based on the use of high resolution images and the application of automatic change detection by computation and comparison of digital surface models and building extraction techniques. Results from a pilot application of the proposed procedure are given together with an estimated cost for application of this method to the coastal zone of eastern Attica, a Greek prefecture with many existing and emerging informal constructions.