The Thousand Islands

Indonesia is the world's fourth most populous country in the world after China, India, and the United States. Estimated population up to April 2007 is 248,287,819, giving it an average population density of 123 persons per sq km (319 per sq mi). More than half the people live on Java, where Jakarta, Indonesia's capital and largest city, is located. It homes more than 491 ethnic groups, speak more 567 different languages or dialects.

Followers of Islam make up 87 percent of the population, making Indonesia the most populous Muslim-majority nation in the world. Christians represent 9 percent of the population. Most of these belong to the Protestant Church in Indonesia, a merger of several Protestant sects. There are also many other locally organized Protestant groups, such as the Batak Protestant Christian Church, which claims about 2 million members. About 2 percent of the population is Roman Catholic. Buddhists, most of whom are of Chinese descent, account for about 1 percent of the population. Hinduism was once a major influence throughout the region but is now significant only on Bali.

Indonesia is located south and east of mainland Asia and north and west of Australia. About half of Indonesia's of more than 17,000 islands are inhabited; all are located in the Indian and Pacific oceans. This makes Indonesia the largest archipelagic country in the world.

The length of Indonesia from East to West is about 5,100 km (about 3,200 mi). This makes nearly similar two times distance from Hong Kong to Singapore. The length from North to South is about 1,900 km (about 1,200 mi). This makes nearly similar the distance a little farher from Hong Kong to Beijing. The country's total land area is 1,904,443 sq km (735,310 sq mi). The rest area is sea. Total coastline of Indonesia is about 54,720 km (about 34,000 mi). This makes the longest coastline in the world after Canada.

Indonesia is surrounded by the South China Sea, the Celebes Sea, and the Pacific Ocean to the north, and by the Indian Ocean to the south and west.

The main islands of Indonesia are Java (Jawa), Sumatra (Sumatera), and Sulawesi (Celebes). The republic shares the island of Kalimantan (Borneo) with Malaysia and Brunei Darussalam; Indonesian Kalimantan makes up about 75 percent of the island and is called Kalimantan. Indonesia also shares the island of New Guinea with Papua New Guinea; Indonesia occupies the western half of the island, known as Papua (formerly Irian Jaya).

MAP OF INDONESIA

Because of its tropical climate and geography, much of Indonesia's population lives near water, either on the coast or by rivers and lakes. Indonesia has no major rivers that are similar in size or scope to the Mekong or Yangtze in mainland Asia, but it does have many important rivers. Kalimantan has the largest rivers, including the Mahakam in East Kalimantan and the Martapura and Barito in South Kalimantan. Most of these rivers originate in the island's central massif (mountain mass) and meander through extensive swamps as they approach the coast. Settlements such as Samarinda and Banjarmasin cluster along the rivers, which serve as communication routes into the interior.

The largest rivers on Sumatra drain from west to east into the Strait of Malacca. In the north, the Asahan River once linked trade between the Batak people who live inland and the Malay people who live along the coast. The Asahan is now dammed, however, and produces hydroelectricity for the industries of North Sumatra. In the south, river ports such as Jambi on the Hari River and Palembang on the Musi River are located upstream, away from the extensive mangrove swamps and marshes of the coast. Passenger ferries and small riverboats provide services along the main rivers.

Papua has more than 30 major rivers draining to the north and south from the Maoke Mountains, which run through the center of the province. One of the most significant is the 400-km (250-mi) Baliem River, which rises in the Jayawijaya Mountains and drains into the Arafura Sea. Many tribal groups, including the Dani and the Asmat, live along the river and its tributaries.

The main rivers of Java include the Tarum and Manuk in the west, the Serang and Serayu in central Java, and the Solo and Brantas in the east. All meander across the broad lowlands of Java, and several are laden with silt due to the extensive farming in their basins.

Lake Toba, the largest of Indonesia's lakes, is situated on Sumatra's Batak Highlands in the Barisan Mountains, about 180 km (about 110 mi) south of Medan. Surrounded by steep mountain cliffs and sandy beaches, Lake Toba covers 1,145 sq km (442 sq mi) and features Samosir Island in its center. The lake is the source of the Asahan River, and as the center of Batak culture it is an important tourist destination.

Lake Tempe, in the center of South Sulawesi province, is another important lake, although it is shrinking in both size and significance. Tempe is thought to be a remnant of an inland sea that once divided the peninsula on which it sits. The lake is now fed by the Walanae River and is an important source of fish and shrimp (called lawa), which are used both locally and for export. In order to make Tempe more productive, the government at one time restocked it with fish that do not compete with each other for food. Because of siltation from nearby farms, Tempe is now less than 2 m (6 ft) deep, and large parts dry up in the dry season.

Other significant lakes include Maninjau, Kerinci, and Singkarak in Sumatra; Towuti, Sidenreng, Poso, Tondano, and Matan in Sulawesi; Paniai and Sentani in Papua; Jempang, Melintang, and Semayang on Kalimantan's Markaham River; and Luar, Sentarum, and Siawan on the upper reaches of Kalimantan's Kapuas River.

With 40,000 species of flowering plants, including 3,000 trees and 5,000 orchids, Indonesia has a greater variety of flora than the tropical regions of Africa or the Americas. Indonesia is home to the very large and smelly corpse lily (Rafflesia). Orchids are also abundant, and Indonesia is home to the largest of all orchids, the tiger orchid. The insect-trapping pitcher plant is found throughout western Indonesia.

Tropical rain forests prevail in the northern lowlands of Indonesia. Tall tropical hardwoods dominate the forests and provide good harvests of timber, resin, vegetable oil, and illipe nuts. Mangrove trees and nipa palm dominate the forests of the southern lowlands. The hill forests consist of oak and chestnut trees and mountain plants.

The animals of Indonesia are separated by Wallace's Line into the Indo-Malayan and Austro-Malayan zoogeographic regions. The Indo-Malayan region includes Java, Kalimantan, and Sumatra and has species linked to mainland Asia. Orangutans live in the forests of Sumatra and Kalimantan. Wild oxen, also known as banteng, are in Kalimantan and parts of Java such as the Ujung Kulon National Park in western Java. Proboscis monkeys (bekanten) can be found in Kalimantan, and elephants, tapir, and siamangs (black gibbons) inhabit Sumatra.

The animals of the Austro-Malayan region are linked to Australia. Papua is home to the large, flightless cassowary bird and to many species of colorful birds of paradise.

Maluku, Sulawesi, and the Lesser Sunda Islands lie between the two larger regions and have somewhat distinctive animals drawn from both. Maleo birds are native to Sulawesi. The phalanger, an Australian type of marsupial, is found on Timor. The Komodo dragon, of Komodo and Rinca islands, is the world's largest lizard, growing to 3 m (10 ft) in length.

Tropical forests cover 55 percent of the land, although this proportion has been shrinking due to deforestation. Trees of the Dipterocarp family, such as the meranti, are a valuable forest resource. Also important are ramin, sandalwood, ebony, and teak. Teak in particular is grown in plantation forests. The government has established many national parks to conserve the natural vegetation and native wildlife. Indonesia claims that little or no commercial development is permitted in about half its forests. The more important national parks include Gunung Leuser (in northwestern Sumatra), Kerinci Seblat (in central Sumatra), Bukit Barisan Selatan (in southern Sumatra), Ujung Kulon (in western Java), Tanjung Puting (in central Kalimantan), and Komodo Island (between Sumbawa and Flores).

Indonesia has significant deposits of oil and natural gas, most of which are concentrated along the eastern coast of Sumatra and in and around Kalimantan. Indonesia produces more than 80 percent of Southeast Asia's oil and more than 35 percent of the world's liquefied gas. Tin on Belitung and Bangka islands, bauxite on Bintan Island, copper in Papua, nickel on Sulawesi, and coal on Sumatra are Indonesia's major mineral resources. Small amounts of silver, gold, diamonds, and rubies are also found. Large parts of Indonesia, especially in Kalimantan and Papua, have not been intensively explored for minerals. The seas surrounding Indonesia yield abundant saltwater fish, pearls, shells, and agar (a substance extracted from seaweed).

Because of Indonesia's location near the equator and its island geography, the climate along coastal areas is hot and humid year-round. The average daily temperature range of Jakarta is 21° to 33°C (69° to 92°F) and varies little from winter to summer. Temperatures in upland areas tend to be cooler. On the top of the Mount Jaya Wijaya on the Papua Island, the temperature even minus 0° C, it covers the year-round snow.

Indonesia has two monsoon seasons: a wet season from November to March and a dry season from June to October. Between monsoons, the weather is more moderate. The northern parts of the country have only slight differences in precipitation during the wet and dry seasons. Average rainfall in the lowlands varies from 1,780 to 3,175 mm (70 to 125 in) per year, and in some mountain regions rainfall reaches 6,100 mm (240 in) per year. The regions with the highest rainfall include the mountainous western coast of Sumatra and the upland areas of western Java, Kalimantan, Sulawesi, and Papua. Humidity is generally high, averaging about 80 percent yearly.

The driest parts of the country, with annual rainfall under 1,000 mm (40 in), are along the coast of the Lesser Sunda Islands and the easternmost end of Java. The erratic seasonal distribution of rain in these areas makes farming difficult.

Indonesia lies beyond the typhoon zone of the western Pacific and the especially powerful storms of the South China Sea. Occasionally a typhoon sweeps through the eastern seas but rarely reaches the Java Sea.

The coral reefs that fringe the country's many islands are of great importance in preserving marine biodiversity.