All-sky maps can also be produced to show large structures or the position of a catalog in the big picture. Catalogs can also be plotted over contour or halftone images. In addition, parameters can be modified on the command line or values returned, so the Unix shell can be used for batch operation of programs. Although this is a fairly rudimentary system, it has been in use for several years and is fairly well debugged. The parameter file is very simple.
Character strings get no special treatment.
While the order of the elements of the line is important, the parsing subroutines will omit leading and trailing spaces and tabs from each element, so they may be positioned for clarity. All of the IRAS map projections are included so objects can be plotted against contoured IR sky flux. The map may be labeled using terminal or computer-generated characters. Computer drawn characters use the Hershey font set and are, in decreasing detail, Complex, Italic, Duplex, and Simplex. The font size may be set separately for headings, tickmark labels, axis labels, time tag, plate scale, and magnitude scale table.