Philippines. Board of Technical Surveys and Maps. Philipines. Department of National Defense. Sheet 3263 IV. Sources: U.S. Army Map Series 711. Compiled in 1956 by photogrammetric methods using 1947-1953 photographs and others. Transverse Mercator projecton. Depths in [meters]. Relief shown by spot elevation and contour lines at 20 meter intervals with supplementary contours at 5 and 10 meter intervals.