Numerical Classification, Subak Zoning and Land Transfer Function Rice Field in the Province of Bali Based on Remote Sensing and GIS

Several regulations at the province as well as administrative districts level regarding on the zonation of Subak, are to protect agricultural lands in the sustainable context. Such kinds of rules are included in: Law No. 41/2009, Government Regulation (GR) No.11/2010, GR No. 15/2010, GR No.1/2011, GR No.12/2012, GR No.25/2012, GR No.30/2012, and the Ministry of Agriculture's regulation No.07/Permentan/OT.140/2/2012.Moreover, about 4700 ha paddy fields converted into other uses during 3 years (3 ha/day), especially in the wetland area, have been included in the Spatial Planning. In this study, several types of satellite images were used; Quickbird, Aster, Landsat 8, and Globe 2012-2013, in order to map the land use and land cover change from 2002to 2013. Some thematic maps, such as: watersheds boundary, land use, irrigation, topographic, rainfall, regional spatial planning, land suitability, land productivity and road network, are used as the spatial databases, variable parameters and adjusted weighting scores in the model analysis. The analysis employed those thematic maps and numerical classification of Subak zonation through overlaid and reselects procedures in ArcGIS. As the category thresholds, numerical classification with the total value greater than 125, the Subak zone needs to be protected, the value between of 100-125, it will be designated as the Subak buffer zone, and the values less than 100, it can be converted into other uses. As the results, there are about 53% (43,021.42 ha) of rice field in 2013 should be conserved for in the next 40 years; designated as the buffer zone of Subak 40,31% (38,398.38 ha), and the area can be converted to other uses about 14.26% (13,542.14 ha).