Mangrove Analysis Using ALOS Imagery in Hai Phong city, Vietnam Pham Tien Dat* a, b , Kunihiko Yoshino c a Center for Agricultural Research and Ecological Studies (CARES), Hanoi University of Agriculture (HUA), Trau Quy, Gia Lam, Hanoi, Vietnam; b Graduate School of Life and Environmental Sciences, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki, 305-8577 Japan; c Faculty of Engineering, Information and Systems, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki, 305-8573 Japan. ABSTRACT Mangroves that appear in the inter-tidal zones along the coast in most tropical and semi-tropical countries play a vital role in coastal zones and can defend against the impacts of tsunamis. Nevertheless, these forests are under severe threat because of high population growth, weak governance, poor planning, as well as uncoordinated economic development. Hai Phong city is located on the Northern coast of Vietnam where the mangroves are distributed between zone I and zone II among the four mangrove zones in Vietnam. This city is vulnerable to rising sea levels and tropical cyclones, which are forecasted to become more severe in coming next decades. The objectives of this research were to analyze the current status of mangroves using different ALOS sensors in Hai Phong, Vietnam in 2010 and compare the accuracy of the post satellite image processing of ALOS imagery in mapping mangroves. A combination of object-based and supervised classification was used to generate the land cover maps. The results of this research indicate that the total area of mangrove was approximately 2,549 hectares and mangrove is present in the five coastal districts in Hai Phong. The findings of this research showed that ALOS AVIR-2 provides better accuracy than ALOS PALSAR. This research indicates the potential of utilizing image segmentation associated with supervised method for both optical and SAR images to map mangrove forests in coastal zones Keywords: Mangrove analysis, Object-based classification, supervised classification, ALOS imagery, Hai Phong. 1. INTRODUCTION Mangrove forests appear in the inter-tidal zones along the coast in most tropical and semi-tropical regions [1]. They are among the most important and productive of ecosystems and are found along the coastal zones and offshore islands. Mangroves play an important role in coastal zones and can reduce damage from the effects of tsunamis. The most obvious evidence can be found from the Indian Ocean tsunami of Dec, 2004 [2]. Moreover, mangrove ecosystems stabilize coastlines, clean water, protect the land from erosion, and in many cases promote coastal accretion, and provide a natural barrier against storms, cyclones, tidal bores and other potentially damaging natural forces. For centuries, mangroves have contributed significantly to the socio-economic lives of coastal dwellers. In addition, they are a source of timber for fire-wood and provide building materials, charcoal, tannin, food, honey, herbal medicines, and other forest products [3]. Nevertheless, mangroves are under severe threat. High population growth, and migration into coastal areas, has led to an increased demand for their products. The situation is further exacerbated by insufficient governance, poor planning, and uncoordinated economic development in the coastal zone. Globally more than 3.6 million hectares of Mangroves have been lost since 1980. Asia has suffered the greatest loss of 1.9 million hectares [4]. Like many other countries in Southeast Asia, the mangrove areas in Vietnam have decreased markedly. In Vietnam, it is estimated that the area of mangrove forests was about 400,000 hectares in the early 20 th century. However, this area has declined dramatically during the past 50 years [5]. In northern parts of Vietnam, from Mong Cai to Do Son, throughout the periods 1964-1997, mangrove area decreased by 17,094 ha. In the Red River plain, the loss of mangrove was 4,640 ha from 1975 to 1991 followed by a decrease of 7,430 ha in 1993 [6]. Therefore, it is necessary to monitor mangroves, and mapping of the mangroves is important in order to support coastal zone management and planning programs. * dat6784@gmail.com; phone 84 43 8765607; fax 84 43 8766642; sky@sk.tsukuba.ac.jp Remote Sensing of the Marine Environment II, edited by Robert J. Frouin, Naoto Ebuchi, Delu Pan, Toshiro Saino, Proc. of SPIE Vol. 8525, 85250U © 2012 SPIE · CCC code: 0277-786/12/$18 · doi: 10.1117/12.977261 Proc. of SPIE Vol. 8525 85250U-1 Downloaded From: http://proceedings.spiedigitallibrary.org/ on 07/20/2016 Terms of Use: http://spiedigitallibrary.org/ss/TermsOfUse.aspx