Paper Title
Water Demands Estimation on Agriculture Area Using Geographic Information System

Abstract
Most agricultural in Samut Songkhram Province, Thailand were planting crops such as grapefruit, coconut and lychee around 62% of total area, which are famous and generate a lot of income for farmers. Samut Songkhram Province has three water resources that were fresh water, brackish and salt water. The soil water in term of soil moisture is an indicator for measure of the quality and yield of agricultural products. Researchers interested to studying the evaluation of the soil water using geographic information system, remote sensing with 30x30 pixels size from Landsat 8 satellite and using balance water equation. This research considers the four main parameters which were; estimation of spatial rainfall runoff and quantity of evaporation, infiltration rate of the soil. To evaluate the amount of soil water in order to create soil moisture map for planning the utilization and management of water for agriculture. The results show the average precipitation, soil moisture, the evaporation, runoff permeability and soil moisture. Moreover, the information of this research was used to plan and make the decision of growing appropriate plants according to the soil moisture of the agriculture. Index Terms - Geo-informatics, Geographic Information System, Remote sensing, Water Demands, Samut Songkhram