The simplest form of plotting is to draw symbols (termed markers) at a set of points. This is performed by AST_MARK, which is supplied with a set of physical coordinates at which to place the markers:
INCLUDE 'AST_PAR' INTEGER NCOORD, NMARK, TYPE, STATUS DOUBLE PRECISION IN( NMARK, NCOORD ) STATUS = 0 ... CALL AST_MARK( PLOT, NMARK, NCOORD, NMARK, IN, TYPE, STATUS )
Here, NMARK specifies how many markers to plot and NCOORD specifies
how many coordinates are being supplied for each
array IN supplies the coordinates and the integer TYPE specifies which
type of marker to plot.
AST A Library for Handling World Coordinate Systems in Astronomy