The Defense Mapping Agency has cleared another hurdle in its effort to transfer more than 600 employes from the Suitland Federal Center in Prince George's County to the Brookmont area of Montgomery County, a move that is opposed by almost everyone involved except the Defense Department.

U.S. District Judge Aubrey Robinon ruled this week that the Pentagon can go ahead with plans to consolidate its hydrographic center, which makes charts of the sea for the Navy, with its topographic command, which makes land maps. The Pentagon says moving of the sea chart makers into the Brookmont facility, already occupied by about 2,300 topographic command employes, will save taxpayers $5 million a year.

The judge made his ruling in a suit filed against the Defense Department by the Maryland-National Capital Park and Planning Commission, more than 20 Montgomery County civic groups, a labor union representing the Suitland employes and ABC News commentator Howard K. Smith and his wife, Benedicte, who lived next door to the Brookmont installation.

The suit contended that military officials, in planning the change, did not give enough consideration to the effects of increased traffic and congestion that the move would cause and did not make an adequate environmental impact study.

Robinson said, however, that the consolidation of the mapping commands would not significantly affect the environment and that the Pentagon did not act arbitrarily in its decision not to make a full environmental impact statement. The judge said the move could be compared to the action of any agency that hired new employes at an existing facility.

"We are considering very seriously filing an appeal," said William Green, the attorney representing two of the civic organizations, the Potomac Valley League of Montgomery County, a coalition of 22 citizen organizations, and the Civil League of Brookmont and Vicinity, Inc.

"We view this proposed move as a threat to the entire area" around the mapping agency's Brookmont installation, Green said. He said that moving 600 people into the area would have a serious impact on water and sewer facilities and housing in what he termed "a very fragile community." The Potomac Valley League "has fought for years to preserve the palisades of the Potomac; they're a national treasure," Green added.

The Prince George's County-based employes, who are represented by the American Federation of Government Employes local 3407 in the suit, have protested the extra time and expense of either driving across the city in rush-hour traffic or moving to the more expensive Brookmont area.

In Suitland, the Hydorgraphic Center is sticking to its original schedule for the move to Montgomery County, said Navy Capt. James Schlank, head of the center, who added that there "never were any plans to do otherwise."

The move will take place about the middle of September, he said. Some employes who retire or resign before the move will not be replaced, putting the number who will make the transfer at "just over" 600, Schlank said. About 700 persons were originally employed in the Suitland offices.

No external construction will be required at the Brookmont installation to accomodate the added workers, he said. "We will make internal modifications . . . There is sufficient space for everybody to move into there," Schlank added. He said that officials "want to investigate and see what we can do to enhance parking" for the new workers who commute, but added that "the best indications are that there is adequate parking" space.