Fig 1.
Study area (republished satellite data under a CC BY license, with permission from the Department of Remote Sensing, Ministry of Natural Resources and Environment of Vietnam, original copyright [1995, 2004, 2015]).
Fig 2.
The survey in a sampling plot in the study area (Source: Photo taken by Pham Minh Hai (the author) in the study area in 2019).
Fig 3.
Flow chart of classification using Random Forest algorithm (Source: https://www.section.io/engineering-education/introduction-to-random-forest-in-machine-learning/).
Fig 4.
The illustrations of some training samples for the satellite image classification.
Fig 5.
Sample collection for the random forest algorithm input (republished satellite data under a CC BY license, with permission from the Department of Remote Sensing, Ministry of Natural Resources and Environment of Vietnam, original copyright [1995, 2004, 2015]).
Fig 6.
Indicators for the mangrove health assessment.
Fig 7.
The Percentage of Like Adjacency index (PLADJ) showed high correlation coefficient in the Heat map.
Table 1.
Description of the spatial metrics used in this study (McGarigal et al. 2002).
Table 2.
Classes of indicator value.
Fig 8.
The flow chart developed in the study.
Fig 9.
Satellite image classification results (republished satellite data under a CC BY license, with permission from the Department of Remote Sensing, Ministry of Natural Resources and Environment of Vietnam, original copyright [1995, 2004, 2015]).
Fig 10.
Change of mangrove areas in Ca Mau from 1995 to 2015.
Fig 11.
The visual comparison between the results of the image classification and the Forest inventory maps (republished satellite data under a CC BY license, with permission from the Department of Remote Sensing, Ministry of Natural Resources and Environment of Vietnam, original copyright [1995, 2004, 2015]).
Table 3.
The confusion matrices of classified classes.
Fig 12.
Mapping factors influencing mangrove health in Ca Mau: (a). The Mangrove canopy width map; (b). The Mangrove fragmentation map; (c). The Mangrove density map; (d) The Mangrove diversity map; (e). and The Mangrove health map. (Republished satellite data under a CC BY license, with permission from the Department of Remote Sensing, Ministry of Natural Resources and Environment of Vietnam, original copyright [1995, 2004, 2015]).
Fig 13.
(a). Changes of spatial metric indices from 1995 to 2015, (b). Mangrove health change detection maps from 1995 to 2004, (c). Mangrove quality change detection maps from 2004 to 2015. (Republished satellite data under a CC BY license, with permission from the Department of Remote Sensing, Ministry of Natural Resources and Environment of Vietnam, original copyright [1995, 2004, 2015]).
Fig 14.
Changes of the mangrove health influencing factors overtime.
Fig 15.
The bridge to the landmark at the end of the National 1st highway (left side) and ecological forest shrimp farms (right side).