This line shapefile displays graticules (grid lines of latitude parallels and longitude meridians) for the world at 20 degree intervals. Graticules include 180-degree east and west meridians (consider deleting one of these to avoid duplicate lines). This layer is part of the Natural Earth Collection (v.2.0.0). Natural Earth is a public domain map dataset available at 1:10m, 1:50m, and 1:110 million scales. Featuring tightly integrated vector and raster data, with Natural Earth you can make a variety of visually pleasing, well-crafted maps with cartography or GIS software. Kelso, N. V. and Patterson, T. (2012). 15-Degree Graticule Grid, World, 1:10 million, 2012. Made with Natural Earth, online at http://www.naturalearthdata.com.