Monitoring urban growth patterns is an important measure to improve our understanding of land use/land cover (LULC) changes and a central part in the proper development of any city. In this study, we analyzed the changes over a period of 30 years (1985–2015) in Bahir Dar, one of the rapidly growing cities of northwest Ethiopia. Satellite images of Landsat TM (1985, 1995, and 2008), and OLI (2015) were used. The classification was carried out using the object-based image analysis technique and a change analysis was undertaken using post-classification comparison in GIS as a novel framework. An accuracy assessment was conducted for each reference year. Eight LULC types were successfully captured with overall accuracies ranging from 88.3% to 92.9% and a Kappa statistic of 0.85 to 0.92. The classification result revealed that cropland (66%), water (12.5%), and grassland (6%) were the dominant LULC types with a small share of areas covered by built-up areas (2.4%) in 1985. In 2015, cropland and water continued to be dominant followed by built-up areas. The change result shows that a rapid reduction in natural forest cover followed by grassland and wetland occurred between the first (1985–1995), second (1995–2008), and third (2008–2015) study periods. On the contrary, build-ups increased in all three periods by 9.3%, 121.3%, and 44.8%, respectively. Although the conversion between the LULC classes varied substantially, analysis of the 30-year change matrix revealed that about 31% was subject to intensive change between the classes. Specifically, the built-up area has increased by 250.5% during the study years. The framed approach used in this research is a good repeatable example of how to assess and monitor urban growth at the local level, by combining remote sensing and GIS technologies. Further study is suggested to investigate detailed drivers, consequences of changes, and future options.

中文翻译：

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利用30年Landsat影像记录监测埃塞俄比亚西北部快速发展的巴希尔达尔市的城市增长模式

监视城市增长模式是提高我们对土地利用/土地覆盖（LULC）变化的理解的重要措施，也是任何城市正常发展的重要组成部分。在这项研究中，我们分析了埃塞俄比亚西北部快速发展的城市之一巴希尔达尔（Bahir Dar）30年间的变化（1985-2015年）。使用Landsat TM（1985、1995和2008）和OLI（2015）的卫星图像。使用基于对象的图像分析技术进行分类，并使用GIS中的后分类比较作为新框架进行变化分析。每个参考年都进行了准确性评估。成功捕获了8种LULC类型，总体准确度在88.3％至92.9％之间，Kappa统计量在0.85至0.92之间。分类结果显示，农田（66％），水（12。5％）和草地（6％）是主要的LULC类型，1985年被建成区覆盖的区域所占比例很小（2.4％）。2015年，耕地和水继续占主导地位，其次是建成区。变化结果表明，在第一个研究阶段（1985-1995年），第二个研究阶段（1995-2008年）和第三个研究阶段（2008-2015年）之间，天然林覆盖率迅速下降，其次是草地和湿地。相反，在这三个时期中，建筑面积分别增加了9.3％，121.3％和44.8％。尽管LULC类别之间的转换差异很大，但对30年变化矩阵的分析显示，约31％的类别之间发生了剧烈变化。具体而言，在研究年度中，建筑面积增加了250.5％。本研究中使用的框架化方法是一个很好的可重复示例，该示例说明了如何通过结合遥感和GIS技术来评估和监控地方一级的城市增长。建议进行进一步研究，以调查详细的驱动因素，变更的后果以及未来的选择。