1.   Clarke had a passionate interest in calculating the figure of the Earth, another central problem for an accurate topographical survey.

2.   --- The first detailed topographical survey of the north pole of Mars has been completed, and the results may force some changes in theories about the planet.

3.   To map the mine fields, Willoughby said, the Halo Trust teams conducted topographical surveys using equipment that measured standard latitude and longitude measurements.

4.   The company will perform exploration, repairs to wells and topographical surveys in Syria, the agency said.