Indonesia is an archipelagic country with the total number of 17,508 islands according to the indonesian naval hydro-oceano-graphic office. The archipelago stretching through several oceans and seas between the pacific and the indian ocean, and bridges two continents, asia and australia.
The territory of the republic of indonesia stretches from 6°08' north to 11°15' south latitude, and from 94°45' to 141°05' east longitude. The indonesian seas and oceans comprise 81 % of the total area of the republic which has a land area of 1.9 million square kilometers.

The five main islands are: sumatra, which is about 473,606 sq. Km. In size; the most fertile and densely populated islands, java/madura, 132,107 sq. Km; kalimantan, which comprises two-thirds of the island of borneo and measures 539,460 sq. Km; sulawesi, 189,216 sq. Km; and irian jaya, 421,981 sq.km, which is part of the world's second largest island, new guinea. Indonesia's other islands are smaller in size.

Indonesia is divided into three geographic segments; the islands of sumatra, java and kalimantan and the small islands in between lie on the sunda shelf where the depth of sea reaches a maximum of 233 metres. Irian jaya and the aru islands lie on the sahul shelf where the sea depth is similar. In between are the islands of nusa tenggara, sulawesi and the malukus where the sea depth descends to on incredible 5,000 metres.

The land area is generally covered by thick tropical rain forests, where fertile soils are continuously replenished by volcanic eruptions like those on the island of java.

The country is characterized 64 mountainous interiors with some 400 volcanoes, of which 100 are active. Mountains higher than 9.,000 feet are found on the islands of sumatra (mt. Leuser and mt. Kerinci), java (mt. Gede, mt. Tangkubanperahu, mt. Ciremai, mt. Kawi, mt. Kelud, mt. Semeru and mt. Raung), sulawesi (mt. Lompobatang and mt. Rantekombala), bali (mt. Batur and mt. Agung), lombok (mt, rinjani) and sumbawa (mt. Tambora). The highest mountain is the perpetually snow-capped mandala top (15,300 feet) in the jaya wijaya mountain range of irian jaya.
Many rivers flow throughout the country. On certain islands they serve as useful transportation routes, for example, the musi, batanghari, indragiri and kampar rivers in sumatra; the kapuas, barito, mahakam and rejang rivers in kalimantan; and the memberamo and digul rivers in irian jaya.

A number of islands are dotted with scenic lakes, like the toba, maninjau and singkarak lakes in sumatra; the tempe, towuti, sidenreng, poso, limboto, tondano, and matana lakes in sulawesi; and the paniai and sentani lakes in irian jaya.

Climate

The climate and weather of indonesia is characterized by two tropical seasons, which vary with the equatorial air circulation (the walker circulation) and the meridian air circulation (the hardley circulation). Indonesia's monsoon-type climate changes approximately every six months although in recent years weather patterns have been somewhat disrupted as part of global changes in weather. Humidity and temperatures vary according to the season but temperatures are affected additionally by time of day, height above sea level and proximity to the sea an exception. The dry season is from june to september and the rainy season from december to march. Intervening periods are transition months in which the weather will be mixed.

Average temperatures are classified as follows:
Coastal plains: 28°c
Inland and mountain areas: 26°c
Higher mountain areas: 23°c, varying with the altitude. Indonesia has an average relative humidity between 70% and 90%, with a minimum of 73% and a maximum of 87%.


Indonesia standard time

Indonesia is three time zones are as below:

1. Western indonesia standard time equals gmt plus 7 hours (meridian 105°e), covering all provinces in sumatra and java,. And the provinces of west and central kalimantan.

2. Central indonesia standard time equals gmt plus 8 hours (meridian 1200e), covering the provinces oil east and south kalimantan, all provinces in sulawesi, and the provinces of bali, west and east nusatenggara.

3. Eastern indonesia standard time equals gmt plus 9 hours (meridian 135°e), covering the provinces of maluku and irian jaya.
Exclusive economic zone

When independence was proclaimed and sovereignty gained indonesia had to enact laws to govern the seas in accordance with the geographic structure of an archipelagic state. This, however, did not mean that the country would bar international passage. The laws were necessary instruments for the unity and national resilience of the country, with a territory that embraces all the islands, the islets and the seas in between.

In view of the country's susceptibility to foreign intervention from the sea and for domes tic security reasons, on december 13, 1957, the indonesian government issued a declaration on the territorial waters of the republic. It stated that all the waters surrounding and between the islands in the territory carne within indonesia's sovereignty. It also de- termined that the country's territorial water limit was 12 miles, measured from a straight baseline drawn from the outermost. Points of the islands.

In the past, archipelagic states like indonesia have unilaterally determined their 200-mile-exclusive economic zones. Today such economic zones are confirmed by the international convention on the law of the sea, which was ratified by the indonesian government on october 18, 1983, by act no. 5 of the same year. This is the legal basis of the indonesian-exclusive economic zone.