Lines of striation need not have a material manifestation. For example, grids of latitude and longitude cannot be physically observed on the ground, yet have great power to channel flows of navigation on land and sea. And while they cannot physically be observed, we visualize them in other representational forms such as maps or globes.
[T]he sea is a smooth space par excellence, and yet was the first to encounter the demands of increasingly strict striation. The problem did not arise in proximity to land. On the contrary, the striation of the sea was a result of navigation on the open water. Maritime space was striated as a function of two astronomical and geographical gains: bearings, obtained by a set of calculations based on exact observation of the stars and the sun; and the map, which intertwines meridians and parallels, longitudes and latitudes, plotting regions known and unknown onto a grid (like a Mendeleyev table) (Deleuze and Guattari, 1987, p. 479).
Sport offers similar examples of physical territories with varying degrees of smoothness that have lines of striation superimposed in an invisible, yet well understood fashion. The first down line in gridiron football is a fiction that forces the offensive team to move the ball forward 10 yards within four downs in order to maintain possession. And in association football offsides is understood as the line perpendicular to both sidelines that runs through the last defender on the field which cannot be crossed by an offensive player until after the ball has been passed by a teammate.
Unlike with latitude and longitude, however, these two sporting examples feature moving lines. Their lack of stationary position negates any ability to have a fixed material presence on the field of play. While we also attempt to visualize these moving lines in other representational forms, the frequent line changes and pace of the moving bodies require the medium to be moving as well. Hence the virtual imaging systems currently used in the televisual production of sporting spectacle, such as those shown here by SporTVision, with bearings fixed by multiple cameras surrounding the field of play and lines plotted on a map in virtual space.