Digital mapping of surficial deposits in Khu Bua Area, Changwat Ratchaburi

Abstract

Thematic (GIS and remote sensing) data preparation, laboratory analysis, and field investigation were carried out to generate the surficial deposits map and improve the Quaternary units in Amphoe Muang Ratchaburi, Amphoe Paktho, Amphoe Wat Phleng and Amphoe Dam Noen, Changwat Ratchaburi and Saduak, Amphoe Bang Khonthi, Amphoe Amphawa, Changwat Samut Songkham. The area comprising approximately 170 square kilometers. This research generated map by the combining of classified imagery (satellite image from Landsat8 OLI/TIRS), field investigation data and morphologically defined areas derived from 1m digital elevation models (DEM). The result from this study can discriminate surficial deposits units to 5 units: Unit V is the foothill field which compose of silt with sand, Unit W is the field with stiff grayish yellow silt, Unit X is the field with gray clay, Unit Y is the cropland with soft brown and light brown clay and Unit Z is the wet cropland with soft dark brown and light gray silt. Finally, the field data is also significantly to improve and confirm the exact boundary detail of surficial deposits units from the secondary supervised classification with using field data as training area. Although the digital classification technique cannot use to identify all of the lithologic characteristics but it help us to spend less time in the large area and should be very fruitful to update for the more accurate surficial deposits of the traditional geological data and map in the low land areas. The result from this study is adaptable to support the surficial deposits and materials management in study area and the other applications.