Mangrove vegetation health index analysis by implementing NDVI (normalized difference vegetation index) classification method on sentinel-2 image data case study: Segara Anakan, Kabupaten Cilacap

Abstract

Segara Anakan, Cilacap District is an area that embodies the largest mangrove forest in Indonesia, namely 8,576.06 ha in 2016. The observation and mapping of vegetation index surrounding the forest are done by utilizing remote sensing to acquire satellite images. Plants have adequate reflectance to Near Infrared (NIR) lights. Normalized Vegetation Index (NDVI) is classified to have high accuracy in mapping mangrove in an area. The concept of NDVI is considerably simple, namely by observing the best NIR light reflected by the chlorophyll and red light radiation absorbed by green plants. Algorithm or equation used is (NIR - RED)/(NIR + RED). The results from the algorithm will then be used to derive index value ranging from -1 to 1. This index value will be employed as a parameter to indicate whether the mangroves are healthy or not. This study is done in 2020 incorporating data from 2017 to 2020 that are relevant to Segara Anakan, Cilacap District and implementing NDVI method to analyze the mangroves' health. Results from the satellite images show that mangroves in Segara Anakan are experiencing a negative trend regarding their health from year to year. The result in 2017 shows a majority of 0.9 index with pixel vegetation frequency of 17,500 which drastically declined in 2020 to only 7,000 with majorities of 0,2;0,6;0,8 which is caused by deforestation and natural causes inhibiting the sowing and growth of mangroves.