Identification and Assessment of Chromatic Anomalies Induced by Building Roofs in the Urban Landscape of Romania

Urban images taken from above sometimes show chromatic anomalies induced by the colour of the roofs of certain buildings or of other anthropogenic elements. These observations may often be ignored because of their reduced visibility from ground level, yet they may provide information relevant to sustainable urban management and the conservation of urban identity. Aerial images are at present used ever more frequently in practice and, consequently, the appearance of localities seen from above holds greater importance than in the past. The analysis consists of overlaying building footprints on urban aerial images and then describing in numerical form the colour of each roof. The resulting statistical data series was analysed with respect to its distribution, identifying the outlier values. In order to simplify the entire procedure, a software application was developed, the design of which is described in the paper. Elements were identified which, because of their colour, differ from the chromatic appearance of an area. These may reflect transformations of certain localities. The results obtained come from the research carried out by the authors on three cities in Romania that have considerable architectural value and high tourism potential, and in which numerous rehabilitation and construction works are currently under way. The results may inform local intervention guidelines for sustainable urban management, while chromatic departures require contextual assessment and independent validation.