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Thứ Sáu, 5 tháng 10, 2018

30-year observation of mangrove forest in Vietnam from space

The harmonic function and cloud computing power have been employed to generate mangrove forest covers across the country of Vietnam over 30 years, from 1988 to 2018. To have this done, following techniques and tools have been applied:

  • Data sources: Landsat-5, Landsat-7 and Landsat-8 satellite imagery.
  • Date: 1988 to 2018.
  • Coverage: Country of Vietnam.
  • Tools and techniques: Harmonic function, NDVI, NDWI, cloud-removing technique, java programming language.
  • WebGIS: GISCloud.
  • Data summary: QGIS.

Following table displays total area of mangrove forest by years for different regions/zones in Vietnam. Please take note that those values represent mature mangrove forest area, not the area which were considered mangrove forest.

Table 1. Summary of mangrove forest area over different periods
Unit: ha

Region 1988-1989 1990-1991 1992-1993 1994-1995 1996-1997 1998-1999 2000-2001 2002-2003 2005-2005 2006-2007 2008-2009 2010-2011 2013-2014 2015-2016 2017-2018
North Central Coast 1,020 1,126 1,285 533 1,592 2,696 2,338 1,173 7,526 10,197 4,857 3,534 16,113 9,408 23,512
Red River Delta 1,269 916 771 1,390 1,234 1,750 1,669 1,033 393 565 827 999 1,642 1,798 1,586
North East 5,079 5,441 4,919 6,805 5,224 6,362 5,734 5,624 3,037 2,319 4,817 6,119 9,583 10,080 8,452
Mekong River Delta 97,771 58,969 47,922 48,603 55,346 63,715 68,808 60,911 49,428 48,010 52,957 49,032 67,219 67,975 74,086
South Central Coast 150 169 115 172 187 219 362 112 156 117 331 165 899 899 1,090
South-East South 21,706 18,867 21,635 28,484 33,146 36,641 42,558 41,516 40,950 41,042 40,293 39,729 43,458 44,331 43,682
Total 126,995 85,488 76,647 85,987 96,729 111,383 121,469 110,369 101,490 102,250 104,082 99,578 138,914 134,491 152,408


Fig. 1. Economic zones of Vietnam
Observations from summary data mark two important periods when the mangrove cover got significant change:

  • From 1990-1995: Large area of forest disappeared for shrimp cultivation.
  • From 2005-2010: After some rise in 2000, a big area of mangrove forest had been cut down for aquaculture again. Only after 2010, the sign of regeneration and newly planted forest could have been noticed.

Fig. 2. Evolution of mangrove forest cover from 1988 - 2018



More detail can be found for Mekong River Delta from Table 1, which gives clear elaboration of these notices.

Again, for weekend fun, please play with this WebGIS tool below for your own exploration.









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