Jogyakarta/Yogya/Jogja, Central and Southern Java Special Zone, Indonesia. The Indian Ocean lies to the south. It covers an area of 3,169 square kilometers (1,224 square miles). The western half of the coastal plain is 24 kilometers (15 miles) wide. The soil is formed by lava and volcanic ash. The eastern part of the Kendang Plateau extends from east to west, reaching the coast. The main rivers Ojo, including the tributaries Opak and Progo, flow southward into the Indian Ocean. The inhabitants of coastal lowlands are mainly engaged in agriculture and fishery. It produces rice, rubber, dried coconut nuts and sugar.