Grid maps are identified by eastings and southings using a partly alphabetic scale (to differentiate them from island references)

Each grid map is 11 island-units across by 11 island-units down.

Grid 3x:4x, for example, contains islands in the square from 30:40 to 39:49, and the island at 05:50 would be on Grid map 0x:5x.
0x 1x 2x 3x 4x 5x 6x 7x 8x 9x 10x
0x 0x:0x 1x:0x 2x:0x 3x:0x 4x:0x 5x:0x 6x:0x 7x:0x 8x:0x 9x:0x 10x:0x 0x
1x 0x:1x 1x:1x 2x:1x 3x:1x 4x:1x 5x:1x 6x:1x 7x:1x 8x:1x 9x:1x 10x:1x 1x
2x 0x:2x 1x:2x 2x:2x 3x:2x 4x:2x 5x:2x 6x:2x 7x:2x 8x:2x 9x:2x 10x:2x 2x
3x 0x:3x 1x:3x 2x:3x 3x:3x 4x:3x 5x:3x 6x:3x 7x:3x 8x:3x 9x:3x 10x:3x 3x
4x 0x:4x 1x:4x 2x:4x 3x:4x 4x:4x 5x:4x 6x:4x 7x:4x 8x:4x 9x:4x 10x:4x 4x
5x 0x:5x 1x:5x 2x:5x 3x:5x 4x:5x 5x:5x 6x:5x 7x:5x 8x:5x 9x:5x 10x:5x 5x
6x 0x:6x 1x:6x 2x:6x 3x:6x 4x:6x 5x:6x 6x:6x 7x:6x 8x:6x 9x:6x 10x:6x 6x
7x 0x:7x 1x:7x 2x:7x 3x:7x 4x:7x 5x:7x 6x:7x 7x:7x 8x:7x 9x:7x 10x:7x 7x
8x 0x:8x 1x:8x 2x:8x 3x:8x 4x:8x 5x:8x 6x:8x 7x:8x 8x:8x 9x:8x 10x:8x 8x
9x 0x:9x 1x:9x 2x:9x 3x:9x 4x:9x 5x:9x 6x:9x 7x:9x 8x:9x 9x:9x 10x:9x 9x
10x 0x:10x 1x:10x 2x:10x 3x:10x 4x:10x 5x:10x 6x:10x 7x:10x 8x:10x 9x:10x 10x:10x 10x
0x 1x 2x 3x 4x 5x 6x 7x 8x 9x 10x

It might be noted that this map is rotated 45 degrees counterclockwise from the Ikariam world map.