In the Sector Reference System, a USGS 1:24,000 scale topographic map is divided into many parts (sectors). How many parts?

In the Sector Reference System, a USGS 1:24,000 scale topographic map is divided into many parts (sectors). How many parts?

• A. 9 parts
• B. 6 parts
• C. 12 parts
• D. 3 parts

Answer: (A)

The Sector Reference System uses a simple 3-by-3 grid on a USGS 1:24,000 topographic map, creating nine equal sectors. Lines run across the map at one-third and two-thirds of both the width and height, so the map is effectively divided like a tic-tac-toe board. This setup gives a clear, consistent way to reference any location within the map, which is why there are nine parts in the standard division. Three or six or twelve parts would come from different grid layouts, but the established scheme for these maps is a 3-by-3 arrangement, yielding nine sectors.

The Sector Reference System uses a simple 3-by-3 grid on a USGS 1:24,000 topographic map, creating nine equal sectors. Lines run across the map at one-third and two-thirds of both the width and height, so the map is effectively divided like a tic-tac-toe board. This setup gives a clear, consistent way to reference any location within the map, which is why there are nine parts in the standard division. Three or six or twelve parts would come from different grid layouts, but the established scheme for these maps is a 3-by-3 arrangement, yielding nine sectors.