Okinawa Trough geophysical and topographic modeling by GDAL utilities and GRASS GIS

This paper presents using GDAL utilities and GRASS GIS for topographic analysis of the raster grids based on GEBCO DEM as NetCDF file at 15 arc-second intervals. The focus study area encompasses around Okinawa Trough, Ryukyu trench-arc system, southern Japan, East China Sea Philippine Sea, West Pacific Ocean. Several were applied data processing: gdaldem, gdalwarp, gdalinfo, gdal_translate. imported to via r.in.gdal. Data visualization highlighted high resolution accuracy grid, enabling modelling advanced level. algorithm processing, implemented in utility was used generating multi-purpose models: aspect, hillshade, roughness indices, such Topographic Position Index (TPI), Terrain Ruggedness (TRI). Thematic maps (topography, geoid, marine free-air gravity) visualized modules (d.rast, r.colors, r.contour) vector (d.vect, v.in.region, d.legend) processing. results demonstrated smoother bathymetry rugged relief which corresponds their different geological geophysical settings. presented methodology technical aspects scripting approach cartography.