(1) For the purposes of this Act, the surface of the Earth is taken to be divided:
(a) by the meridian of Greenwich and by meridians that are at an angular distance from that meridian of 5 minutes, or a multiple of 5 minutes, of longitude; and
(b) by the equator and by parallels of latitude that are at an angular distance from the equator of 5 minutes, or a multiple of 5 minutes, of latitude;
into sections called graticular sections , each of which is bounded:
(c) by portions of 2 of those meridians that are at an angular distance from each other of 5 minutes of longitude; and
(d) by portions of 2 of those parallels of latitude that are at an angular distance from each other of 5 minutes of latitude.
Simplified map
(2) This subsection sets out a simplified map illustrating graticular sections off the coast of Western Australia in the vicinity of Barrow Island:
(3) For the purposes of this Act:
(a) a graticular section that is wholly within an offshore area constitutes a block ; and
(b) if a part only of a graticular section is, or parts only of a graticular section are, within an offshore area, the area of that part, or of those parts, constitutes a block .
Note 1: See also section 282 (certain portions of blocks to be blocks).
Note 2: See also section 461A (certain State/Territory blocks to be blocks).
Note 3: See also section 462 (certain portions of blocks to be blocks).
Block that is constituted by a graticular section
(4) A reference in this Act to a block that is constituted by a graticular section includes a reference to a block that is constituted by the area of a part only, or by the areas of parts only, of a graticular section.
Graticular section that constitutes a block
(5) A reference in this Act to a graticular section that constitutes a block includes a reference to:
(a) a graticular section only part of which constitutes a block; or
(b) a graticular section only parts of which constitute a block.
Note: For datum, see section 39.