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Remote sensing is a useful technology for monitoring the spatial distribution and expansion of built-up and bare land areas. One effective approach, known as the normalized difference built-up index (NDBI), has been promoted for identifying built-up areas based on Landsat Thematic Mapper (TM)/Enhanced Thematic Mapper (ETM+) data. The successful launch of the Landsat-8 satellite has made possible the continued acquisition of high-quality data that meet requirements for observing land use and land cover (LULC), and whether or not NDBI approach can be used with Landsat-8 data needs further verification. In this study, we researched the reflectance spectral characteristics of different land cover types in different bands of Landsat-8 operational land imager (OLI) data and found that the trend of some built-up areas in the OLI data from the near-infrared band to the shortwave infrared band is different from that in the TM/ETM+ data. This different trend made the conventional NDBI approach unsuitable for Landsat-8 OLI data. We propose a new index, called the build-up and bare land areas index, for transforming Landsat-8 OLI data to map built-up and bare land areas automatically. This new index was used to detect the built-up and bare land areas in Zhengzhou (Henan, China). The accuracy assessment indicates that our index has much higher accuracy (90.8%) than the conventional NDBI approach does (57.4%).
