Sector dimensions are expressed using what unit?

• A. Minutes of latitude and longitude
• B. Degrees of arc
• C. Miles of distance
• D. Seconds of time

Answer: (A)

Sector dimensions on a map or chart are angular measurements, expressed as arc lengths along the Earth’s surface. Since location is given in latitude and longitude, the size of a sector is described by how many arcminutes of latitude and arcminutes of longitude it spans. An arcminute is a subdivision of a degree, giving precise, small angular extents for a sector. Degrees would be too coarse for small sectors, miles describe linear distance (which varies with latitude on the sphere), and seconds of time aren’t a unit for angular size. Therefore, minutes of latitude and longitude are the appropriate way to express sector dimensions.