Survey of Sri Lanka and a central database General discussion The format described here under, has evolved from the Digital Vector Data (DVD-3) format, which was earlier designed as the National Standard Exchange Format for Survey of Sri Lanka digital Cartographic vector data. This format catered for point, line and polygon topology describing relationships among spatial features. The currently proposed format has the provision to include digital images acquired by satellites and Digital Elevation Model (DEM) and coded raster data. Read more about Survey of Sri Lanka and a central database1 comment