Sample of vector data (actually DLG-O format) derived from U. S. Geological Survey (USGS) topographic maps. Global Mapper will not display DLG-S data, an older format that is no longer sold or supported. Most USGS DLG-Optional data do not contain record delimiters. Global Mapper does not require that delimiters be added, and will display DLG-O data with or without delimiters. Other software may require either the absence or presence of delimiters.