The National Topographic System (NTS) of Canada

The topographic maps produced by Natural Resources Canada conform to the NTS. They are available in two standard scales, 1:50 000 and 1:250 000. The area covered by a given map sheet is determined by its latitude and longitude. Because of the standard NTS numbering system, knowing the map number allows you to quickly identify adjacent maps.

The 1:250 000 scale maps are identified by a combination of numbers and letters, A through P (e.g. 12A). The 1:250 000 blocks are divided into sixteen segments (1 to 16), forming blocks used for 1:50 000 scale mapping (e.g. 12A/1 identifies Cold Spring Pond, Newfoundland).

• The 1:250 000 scale topo map covers the same area as 16 of the 1:50 000 scale maps.
• The 1:50 000 topo covers less area but with much greater detail.