PEMBANGUNAN BASIS DATA SPASIAL UNTUK PEMBUATAN MODEL PREDIKSI PENGARUH PENURUNAN TANAH DENGAN TEKNOLOGI GEO-INFORMASI STUDI KASUS KOTA SEMARANG, JAWA TENGAH = DEVELOPMENT OF SPATIAL DATABASE FOR BUILDING A MODEL TO ...

Semarang city is one of the coastal cities in Indonesia with high population density. The city is a regional center for many dynamic socio-economic activities. Land use conversions were high, while at the same time many natural resources were over-exploited. The condition has some negative impacts to the environment. Many coastal hazards, both natural and man-induced, are faced by the city. Among them are land subsidence, sea level rise, erosion and sedimentation, and flooding from the river and high tide. Land subsidence is a natural event, which is accelerated by human activities. Advancement in geo-information technology provides opportunity to use it to model impact of land subsidence in a coastal urban setting like Semarang city. The research being carried out was a multi year's research project. Activities in the first year were directed mainly toward the preparation and development of large scale spatial and non-spatial data. The following working packages were done: land use inventory, generation of digital elevation model. mapping of high tide flood area, monitoring of coastal environmental changes, and developing non-spatial database. Results of the research were large scale (1:5.000) land use map of Semarang in vector and raster format, map of area inundated by high tide flood, digital elevation model. The changes of coastline in Semarang during 1871 � 2001 were also presented. Part of the non-spatial database resulted from the research have been integrated with the digital map as a prototype of geographic information systems. Key words : land subsidence, hazard, geo-informatio