Modelling for a land suitability analysis of rice terraces on the upland area using the geographic information system (GIS) and analytical hierarchical process (AHP)

Rice fields are the main source of rice production. Rice field expansion is one way to increase rice production. Rice field expansion activities for the upland area in Indonesia are often overlooked due to limited information about the availability of suitable land. In upland areas, rice terraces are often found. Until now, there has been no guideline for determining the suitable location of rice terraces on upland areas. The purpose of this study was to develop a land suitability assessment model for rice terraces using geographic information system (GIS) and the analytical hierarchical process (AHP) on upland areas like the Lake Toba catchment area. There were four important factors for selecting rice terracing plantations: spatial planning, slope, texture, and distance from the river (hydrology). By using the AHP method, a rating has been assigned to each theme layer. To create the suitability map for rice terraces in a GIS setting, all the thematic layers were combined into a single layer using the weighted overlay approach. The results showed that 37.78% were highly suitable, 18.88% were moderately suitable, and 36.95% were marginally suitable for rice terraces. The model can be used to determine the location of rice terraces on upland areas with a high accuracy of about 93%.