SEMF1

• Referring to the annular rim identifies north, south, east and west.
• The four quadrant markers are tapered towards the centre.
• 100 Radial sectors are identified by reference to decimal numbers in the annular rim and alphabet letters in the four quadrants.

SEMF2

• The larger cells are identified using numbers 1 < 57. Each large cell is sub-divided into 4, making a total of 228 cells.
• By reference to the cell number and geographical location each cell can be identified.

SEMF3

• 25 cells are identified by reference to their alpha-numeric position.
• The large asymmetric cut out feature in the rim enables the right view to be easily obtained when placing on a SEM stub.