**4. Discussion**

#### *4.1. Imagery Data on This Study*

Landsat data was used in this study because it maps general land cover classes at a spatial resolution of 30 m for large areas. The identification of mangrove cover based on satellite images is not free from ambiguity. The problems usually occur related to the class representation, mixed pixel effects, and tidal effects [96]. For selecting the images, different seasons and atmospheric conditions must be considered [97]. According to Darmawan et al. (2015) mangrove identification and estimation of above-ground mangrove forest biomass are influenced by tidal height [98]. Therefore, the acquisition of Landsat 5 was carried out on 17 May 1989, at 02:39:43 UTC, Landsat 5 on 24 April 1998, at 02:48:21, Landsat 7 ETM+ on 30 June 2002, at 02:59:41, and Landsat 8 OLI on 26 June 2015, at 03:10:34 occurs at the same tides which are affected by the tidal height (Table 13), and also in April–June in South Sumatra has entered the dry season. In Indonesia, there are only two seasons, namely the rainy season and the dry season. It means that for each tidal effect, the Landsat image and atmospheric conditions are at the same conditions.

**Table 13.** The suitability time of Landsat imagery and tidal height.
