Ha Long—Cam Pha Cities Evolution Analysis Utilizing Remote Sensing Data

Giang Cong Nguyen,Anh Khac Nguyen,Khac Vu Dang,Christiane Weber,Tuan Anh Vu

doi:10.3390/rs14051241

Abstract

Socio-economic development has promoted the modification of land cover patterns in the coastal area of Ha Long, Cam Pha cities since the 1990s. The urban growth, together with intensive coal mining activities, has improved the life quality of residents. However, it has also caused many environmental problems in this region. Change detection techniques based on post-classification comparison were applied for monitoring the spatial and temporal evolution of land covers. The confusion matrix for 2001 and 2019 showed high overall accuracy (97.99%, 94.95%) and Kappa coefficient (0.97, 0.92), respectively. Statistics from classified images have revealed that man-made features increased by about 15.32%, while natural features, mangrove jungles, and water bodies decreased 10.64%, 1.96%, 2.72%, respectively, and urban evolution presents various dynamics, soft in the first period (1991–2001), but stronger in the second period (2001–2019) with different characteristics. The study also expresses the constraint of topographic and geologic resources, which have prevented the urban development in this coastal area. Such obtained results are very important for understanding interactions and relations between natural and human phenomena and they may help authorities by providing indicators and maps able to highlight necessary actions for sustainable development.

Highlights

The statistics of the United Nations showed that the Vietnamese urban population has accelerated from 14.7% in 1960 to 37% in 2020 [1], and the amount of urban centers has rapidly risen in recent years, reaching to 862 in 2020 [2] in comparison with 480 in1986 [3]
The accuracy of change detection highly depends on the classification accuracy, and errors in each classified image are present in the final change products
The outline of features issued from the classified images was visually explicit on Google Earth images to identify the coincidence between these two data sets, on the other hand [89]

Summary

Introduction

The statistics of the United Nations showed that the Vietnamese urban population has accelerated from 14.7% in 1960 to 37% in 2020 [1], and the amount of urban centers has rapidly risen in recent years, reaching to 862 in 2020 [2] in comparison with 480 in1986 [3]. Rapid socio-economic development has promoted urbanization at Ha Long and Cam Pha cities. The urban development has interacted with the intensity of coal mining exploitation, causing significant pressures on the environment with many dynamics at the coastal area of Ha Long and Cam Pha cities, such as the expansion of man-made infrastructures [6], the modification of hydrologic network and topographic surface [7], the dissemination of environmental problems such as air pollution, water pollutions, soil degradation [8], and land subsidence hazard [9], etc. Understanding and monitoring urban evolution over a long period in the coastal area of Ha Long and Cam Pha cities are crucial for various purposes such as land management, public service provision, spatial

Methods

Results

Discussion

Conclusion