Dữ liệu GIS
30-year observation of mangrove forest in Vietnam from space
21:17The 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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