graticule; grid of meridians and parallels
Technical term in cartography and geography for the network of latitude and longitude lines on a map or globe.
The graticule on a map is used to indicate positions accurately.
経線 refers specifically to lines of longitude (meridians), while 経緯線網 is the entire grid of both longitude and latitude lines.
緯線 refers specifically to lines of latitude (parallels), while 経緯線網 is the entire grid of both longitude and latitude lines.
Compound of 経緯 (けいい, longitude and latitude) + 線 (せん, line) + 網 (もう, network). The term is a direct technical translation of 'graticule'.