Water and Environmental Research Institute, University of Guam, Mangilao, GU 96923, USA.
Environ Monit Assess. 2011 Aug;179(1-4):521-9. doi: 10.1007/s10661-010-1760-5. Epub 2010 Nov 12.
Land cover change can be caused by human-induced activities and natural forces. Land cover change in watershed level has been a main concern for a long time in the world since watersheds play an important role in our life and environment. This paper is focused on how to apply Landsat Multi-Spectral Scanner (MSS) satellite image of 1973 and Landsat Thematic Mapper (TM) satellite image of 2001 to determine the land cover changes of coastal watersheds from 1973 to 2001. GIS and remote sensing are integrated to derive land cover information from Landsat satellite images of 1973 and 2001. The land cover classification is based on supervised classification method in remote sensing software ERDAS IMAGINE. Historical GIS data is used to replace the areas covered by clouds or shadows in the image of 1973 to improve classification accuracy. Then, temporal land cover is utilized to determine land cover change of coastal watersheds in southern Guam. The overall classification accuracies for Landsat MSS image of 1973 and Landsat TM image of 2001 are 82.74% and 90.42%, respectively. The overall classification of Landsat MSS image is particularly satisfactory considering its coarse spatial resolution and relatively bad data quality because of lots of clouds and shadows in the image. Watershed land cover change in southern Guam is affected greatly by anthropogenic activities. However, natural forces also affect land cover in space and time. Land cover information and change in watersheds can be applied for watershed management and planning, and environmental modeling and assessment. Based on spatio-temporal land cover information, the interaction behavior between human and environment may be evaluated. The findings in this research will be useful to similar research in other tropical islands.
土地覆盖变化可能是由人为活动和自然力量引起的。流域层面的土地覆盖变化一直是世界关注的主要问题，因为流域在我们的生活和环境中起着重要作用。本文主要关注如何应用 1973 年的陆地卫星多光谱扫描仪（MSS）卫星图像和 2001 年的陆地卫星专题制图仪（TM）卫星图像来确定 1973 年至 2001 年沿海流域的土地覆盖变化。GIS 和遥感技术被整合，从 1973 年和 2001 年的陆地卫星图像中提取土地覆盖信息。土地覆盖分类是基于遥感软件 ERDAS IMAGINE 中的监督分类方法。历史 GIS 数据用于替换 1973 年图像中云层或阴影覆盖的区域，以提高分类精度。然后，利用时间土地覆盖来确定关岛南部沿海流域的土地覆盖变化。1973 年陆地卫星 MSS 图像和 2001 年陆地卫星 TM 图像的总体分类精度分别为 82.74%和 90.42%。考虑到图像中存在大量的云层和阴影，1973 年陆地卫星 MSS 图像的总体分类精度非常令人满意，因为其空间分辨率较粗，数据质量相对较差。关岛南部流域的土地覆盖变化受人为活动的影响较大。然而，自然力量也会影响时空土地覆盖。流域土地覆盖信息和变化可应用于流域管理和规划、环境建模和评估。基于时空土地覆盖信息，可以评估人类与环境之间的相互作用行为。本研究的结果将对其他热带岛屿的类似研究有用。
