Integrated ecological index (IEI) for urban ecological status based on remote sensing data: A study at Semarang - Indonesia

The sustainability of a city will be greatly influenced by its urban ecological status. Remote sensing technology is very supportive for understanding the urban ecological status with advantages in terms of timely, precise and objective, so that has become an increasing concern in the world. In this paper, urban ecological status of Semarang city was analysed by an image of Landsat-8 OLI was acquired in a different season. The urban ecological status is integrated by two main components that are assumed that forming urban land, that is the primary land surface component (i.e. built-up area and vegetation area) and the climate (i.e. land surface humidity and dryness degree). These components are divided into four indicators obtained from the transformation of remote sensing data, which is the NDBI (normalized difference build-up index) for built areas representing the resident aggregation degree, SAVI (soil adjusted vegetation index) for greenness degree, NDMI (normalized difference moisture index) for land surface moisture and NDSI (normalized difference soil index) for the dryness degree. Principal component analysis (PCA) was utilized to compress the four indicators into one to construct the index for assessing overall urban ecological status. The results showed that there were differences in the urban ecological status in different seasons. Urban ecological conditions in the dry season are more varied than in the rainy season. Overall urban ecological conditions in the rainy season are better than the dry season.