Rainfall Analysis of the Makassar City using Thiessen Polygon Method Based on GIS

Abstract

Precipitation is the descent of water from the atmosphere to the surface of the earth which is usually rain, snow, fog, dew and hail, the amount of water falling on the surface of the earth can be measured by rain gauges, the distribution of rain in the space can be known by measuring rain in some locations and areas reviewed. In a variety of human activities, rainfall becomes one of the data needs, especially in the study of water availability for consumption, irrigation building planning and mapping of flooded areas. This study aims to analyze local rainfall data on research objects by utilizing global weather data, the observation period for 15 years i.e., from 2000-2014. This research using Thiessen polygon method based on Geographic Information System (GIS) application, rainfall data sourced from global wheater, accessed on August 28, 2017. The results showed that the distribution of rainfall in the research object is represented by 2 rainfall stations, namely station p_521194 and station p_521197. The highest maximum daily rainfall occurred in 2002 of 149.80 mm while the lowest occurred in 2008 amounted to 68.76 mm. Rainfall data will be used to analyze flood discharge in Makassar city.