This indicate a Radial belonging to a particular Navaid nearby. In this case, it is Radial - 127 off of GVO (Gaviota VORTAC). The radial is simply a magnetic direction running FROM a VOR or TACAN station. When we are ON this radial, our VOR/TACAN radios are capable of indicating this to us via instruments.
Even though we may be ON a radial, our aircraft does NOT have to be heading that direction! We can be flying from the North to the South and PASS by the radial, for a moment our indicators will show us being on the radial, however, we are not pointing that direction. Crabbing against the wind can allow us to be ON a radial and head in a slightly different direction ie. travelling on a 320 radial while flying a heading of 316 because of a left cross wind's effect on our plane.