1) Topographic maps for the areas studied on a 1 : 250,000
scale, produced by the Royal Thai Survey Department.
2) Land satellite images for the areas studied on a 1 : 250,000 as
well as a 1 : 50,000 scale, produced by the Geo-Informatics and Space Technology Development Agency (GISDA)
3) Watershed classification map for the areas studied on a
1 : 50,000 scale, produced by the Office of Environmental
Policy and Planning (OEPP).
4) Government department records on soil, land use, and watershed
classes.