World Latitude and Longitude Grid is a polygon theme representing a 1- by 1-degree latitude-longitude grid covering the world with attributes that allow it to display grids at intervals of 1, 5, 10, 15, 20, and 30 degrees. To display a grid with a 1-degree interval, simply display all of the lines. To display a coarser grid (e.g., a 15-degree interval), in the Layer Properties dialog box, add the DEGREE15 attribute value equal to Y.