William R. MacDonald, 52, an expert in mapping the polar regions who developed a vast and intimate knowledge of Antarctica, died of cancer Wednesday at Anne Arundel General Hospital in Annapolis.

Mr. MacDonald was currently chief of the branch of international activities of the U.S. Geological Survey. His contributions to the mapping of Antarctica were such that a mountain on that continent was named after him in 1961.

These contributions began in 1954, when Mr. MacDonald began compiling maps of Antarctica from aerial photographs taken during Navy projects in the late 1940s. The maps were widely used by scientists in the 1957-58 International Geophysical Year.

Beginning in 1960 and continuing until 1967, Mr. MacDonald spent about six months of each year on the continent, taking part in aerial photography missions to gather material for further mapping. Officials at the Geological Survey believe that he actually may have seen more of the 5.5 million-square miles of Antarctica than any other person.

His responsibilities during this period included the planning and supervision of all the aerial photography missions flown by the Navy for topographical purposes. About 1 million-square-miles were photographed during the seven years in which Mr. MacDonald was in charge of this effort.

"His enthusiasm was absolutely contagious," said Peter Bermel, Mr. McDonald's chief during 1960-67. "He was a very dedicated guy and an effective one in his job."

Mr. McDonald's award included the Meritorious Service Medal of the Interior Department, the Superior Performance Award of the Geological Science Foundation, and the McCormick Civilian Unsung Hero Award, given annually by the Baltimore based spice company to a distinguished citizen of Maryland.

Mr. MacDonald was born in Laurel, and grew up in Washington. He was a graduate of George Washington University and also studied at the U.S. Department of Agriculture Graduate School.

He joined the Geological Survey in 1942, and was assigned to work on Alaska. After World War II service in the Marine Corps, he returned to the survey and worked on the photogrammetric mapping of the Brooks Range in Alaska.

Mr. MacDonald became head of the survey's branch of international activities in 1972.

He was a member of the Antarctican Society, a member of the American Society of Photogrammetry, a member of the American Polar Society, and a member of the Arctic Institute of North America.

Survivors include his wife, Beatrice, of the home in Crownsville, Md; his mother, Ella May MacDonald, of Washington; a sister, Ethel Louise Wooton, of Forestville, Md., and a brother, Duncan J. MacDonald, of Garrett County, Md.

The family suggests that expressions of sympathy be in the form of contributions to the American Cancer Society.