Four years after the last edition went out of print, two versions of a new map showing all Metrobus routes in the District of Columbia will be available Monday.

Both versions show District bus routes on one side, and offer buyers either suburban Maryland or Northern Virginia routes on the other.

The maps, $1 each, will go on sale Monday at all Dart, Drug Fair and Peoples drugstores, at Giant and Safeway stores, at the Metro headquarters building, 600 Fifth St. NW, and at Metro's eight bus division garages and ticket and token outlets.

The maps also will be sold by mail from Metro's office of marketing at the headquarters building.

The 24-by-36-inch map; about the size of a conventional highway road map, folds to 4 by 8 inches. It shows all Metrobus routes and the 37-mile Metro subway system now in operation.

There are more than 1,700 bus route variations throughout the area, according to John Warrington, Metro marketing director. The map is printed in eight colors and routes are color-coded, which Metro officials expect will help users understand a bus network that is regarded as one of the most complicated in the nation.

The map shows, in relatively simple form, the main outer trunks and branches of the routes, and contains insets of downtown Washington and other areas in which numerous routes converge.

The insets use curved arrows to show where routes turn corners. The technique is an effort to deal with areas such as Constitution Avenue in downtown Washington, which alone has 41 segments of routes, Warrington said.

In addition to the map, there is a guide listing each bus route, its normal destination and the general type of service -- all day, rush hour, weekend or late-night "owl." An accompanying directory shows which routes serve tourist attractions and landmarks such as the Capitol, the White House and Washington Cathedral.

After Metro took over the regional bus system from four private companies in 1973, it published and distributed free several editions of a map showing bus routes throughout the area, and also issued and sold a detailed atlas of bus maps.

As sections of the area's subway system were added, however, Metro began an extensive program of adding and rerouting buses to meet new needs, and it became increasingly difficult to issue a bus map that would remain accurate for a reasonable period, Warrington said. a

Metro decided to take advantage of the gap of a year and a half between the opening last fall of the extension of the Blue Line to Addison Road in Prince George's County and next year's scheduled extension of the Red Line from Dupont Circle to Van Ness in Northwest Washington.

Metro plans to issue new editions every six months, Warrington said. Revenue from sales will help pay for new editions, he added.