Accurate and regularly updated information on plastic distribution in urban areas is of great significance for understanding the potential impact of plastic materials on human health and the environment. Remote sensing provides abundant data to identify and map plastics in the natural environment, such as marine plastic debris, and in a heterogeneous urban environment. In existing studies, airborne hyperspectral data were used to map plastic in urban areas. Recently available WorldView-3 data, with superspectral resolution, high spatial resolution and global coverage, have been used in mineral mapping and hydrocarbon detection in non-urban areas. These data provide new opportunities for plastic mapping in urban areas. This study proposes a novel plastic spectral index using WorldView-3 shortwave infrared bands, termed the Normalized Difference Plastic Index (NDPI), to quantify and map plastic materials in urban areas. The NDPI was evaluated in a dense urban area by comparing with the established hyperspectral Hydrocarbon Index (HI) and WorldView-3 Relative-absorption Band Depth (RBD) index. The results demonstrate that the NDPI was effective in visual evaluation, separability analysis and plastic material mapping, with superior performance than the HI and RBD indices. Thus, the proposed NDPI provides a useful measure for urban plastics mapping and analysis.

准确和定期更新有关城市地区塑料分布的信息对于了解塑料材料对人类健康和环境的潜在影响具有重要意义。遥感技术提供了丰富的数据，可以在自然环境（例如海洋塑料碎片）和异类城市环境中识别和绘制塑料图。在现有研究中，机载高光谱数据用于在城市地区绘制塑料图。具有超光谱分辨率，高空间分辨率和全球覆盖范围的最新可用WorldView-3数据已用于非城市地区的矿物制图和碳氢化合物探测。这些数据为在城市地区进行塑料制图提供了新的机会。这项研究提出了一种使用WorldView-3短波红外波段的新型塑性光谱指数，称为标准化差异塑料指数（NDPI），用于量化和绘制城市地区的塑料材料。通过与建立的高光谱碳氢化合物指数（HI）和WorldView-3相对吸收带深度（RBD）指数进行比较，对NDPI进行了评估。结果表明，NDPI在视觉评估，可分离性分析和塑性材料映射方面均有效，其性能优于HI和RBD指数。因此，提议的NDPI为城市塑料制图和分析提供了一种有用的措施。结果表明，NDPI在视觉评估，可分离性分析和塑性材料映射方面均有效，其性能优于HI和RBD指数。因此，提议的NDPI为城市塑料制图和分析提供了一种有用的措施。结果表明，NDPI在视觉评估，可分离性分析和塑性材料映射方面均有效，其性能优于HI和RBD指数。因此，提议的NDPI为城市塑料制图和分析提供了一种有用的措施。