STM Article Repository

Mapping on mangroves using satellite imageries has been developed based on the spectral reflectances characteristics in many vegetation indices. Although the vegetation indices have been widely used and applied in mangrove research with hundreds of scientific publications, most still use the digitization method manually. Satellite imagery is helpful and reduces obstacles in inaccessible stations due to complications of the mangrove root system, thick mud, and loss of the position signals. An urgent demand is to create a mangrove vegetation index capable of tracing and capturing mangrove automatically satisfactorily with canopy density precisely, as shown visually in the satellite images. Aru Islands part of Maluku Province is the Southeast outermost island of the Indonesian archipelagic. The western part of the islands is a cluster of corals and muds from the surrounding river mouths, while in the eastern region, there are small islands with mangrove vegetation surrounded by coral reefs complex. This research is an analytical study on the spectral characteristics of various easily accessible satellite images. The aim is to produce an algorithm to capture and trace the mangroves extent automatically matches as shown visually in the Red-Green-Blue composite image, accurate, easy to operate, faster, and simultaneously display the relative index of mangroves canopy density. As a result, the author proposes an algorithm: ( NIR- Red)/( Red+ SWIR1)*( NIR- SWIR1)/( SWIR1-0.65* Red). The first equation ( NIR- Red)/( Red+ SWIR1) should trace the land, strengthen the spectral vegetation and weaken the spectral features of the waters, such as coral reefs, mudflats, water turbidities, and marine phenomena. The second equation ( NIR- SWIR1)/( SWIR1-0.65* Red) is to trace and capture the spatial of mangroves and display the index of the canopy density. Trial results in many mangroves forests using Landsat 5 TM, Landsat 7 ETM, Landsat 8 OLI, and Sentinel 2 images show satisfactory performance. Spatially, the algorithm capture mangroves extent automatically matches as shown visually in the Red Green Blue composite of the satellite images. The obtained index is significantly correlated to two existing Vegetation Indices, with R2 reaching 0.99. The advantage of the algorithm is that it performs well, easily operationally, produces mangrove maps faster, informs the index, and efficiently monitors the changing of mangrove conditions in a certain period.