Geography of Indonesia
Indonesia is an archipelagic country extending about from east to west and from north to south. According to a geospatial survey conducted between 2007 and 2010 by National Coordinating Agency for Survey and Mapping (Bakosurtanal), Indonesia has 13,466 islands. While earlier survey conducted in 2002 by National Institute of Aeronautics and Space (LAPAN) stated Indonesia has 18,307 islands. According to the CIA World Factbook, there are 17,508 islands. The discrepancy between the surveys is likely caused by the earlier different survey method including tidal islands, sandy cays and rocky reefs that surface during low tide and submerge during high tide. There are 8,844 named islands according to estimates made by the government of Indonesia, with 922 of those are permanently inhabited. It comprises five main islands: Sumatra, Java, Borneo (known as "Kalimantan" in Indonesia), Sulawesi, and New Guinea; two major island groups (Nusa Tenggara and the Maluku Islands) and sixty smaller island groups. Four of the islands are shared with other countries: Borneo is shared with Malaysia and Brunei; Sebatik, located off the northeastern coast of Kalimantan, shared with Malaysia; Timor is shared with East Timor; and the newly divided provinces of Papua and West Papua share the island of New Guinea with Papua New Guinea.
List of beaches in Indonesia
Indonesia is located in a region of abundant coral reefs known as the Coral Triangle as well as being the country with the most volcanoes in the world. Some beaches are derived from fluvial sands and gravels, others from cliff erosion. Coral reefs form white or yellow sanded beaches, while beach sediments derived from volcanic rocks are typically black or grey, such as those of northern Bali and southern Java. In the granitic zone of the Riau, Bangka and Belitung Islands, white quartz sands as well as granite boulders dominate. Sandy backshores are colonized by coastal vegetation, notably "Ipomoea pes-caprae" and "Spinifex littoreus", then coconut and casuarina trees. Coastal dunes are poorly developed in the humid tropics, but on the southern shores of Java and Sumatra, prograded beaches are backed by dunes, some of which carry woodland vegetation. Large deposits of lava and ash from volcanic eruptions may transport large quantities of pyroclastic sediment down to the coast, such as at Mount Merapi in southern Java and Mount Agung in Bali. The area within the Coral Triangle is associated with rich marine biodiversity. Beaches in the area, such as those that are important turtle nesting beaches, are protected by the government.