Grid References and Directions
A point by two numbers
A grid reference names any point by two numbers: how far across and how far up. The pair is written in order, across first and up second, so the point three across and two up is (3, 2). The two numbers together pin down exactly one place, the way a seat is found by row and number. Reading the across value first is the firm rule that stops (3, 2) being confused with (2, 3). Grid references are the language this whole unit uses, because once a point has an address, it can be plotted, read, and used to describe positions and pathways.
Reading a reference
Just as a point can be plotted from its grid reference, a plotted point can be read back into one. Count across from zero first, then up, and write the two numbers in that order. A dot two across and three up is (2, 3), never (3, 2), because across always comes first. This reading is the reverse of plotting, and doing both makes the order stick. Moving freely between a point on the grid and its reference is the core skill of grid systems, and it is exactly how a map turns a location into something you can write down and share.
Directions and turning
Grid systems also use compass directions: north, south, east and west. On a map, up the page is north, down is south, right is east and left is west. A turn changes the way you face by a known amount: a half turn from north faces you south, a quarter turn right from north faces you east. Combining a starting direction with a turn tells you the new direction without guessing. Directions and turns describe movement and facing, complementing grid references, which describe exact location, so a position can be both named and changed.
Following a pathway
A pathway on a grid is a route made of steps along the lines, and its length is the number of unit steps taken. A pathway from (1, 1) across to (3, 1) and up to (3, 3) is two steps across and two up, four units in all. Following a pathway segment by segment, and adding the steps, measures how far the route is, not how far apart the ends are. This is how distances along streets or corridors are found on a grid map, connecting the references of points to the lengths of the journeys between them.
Naming a movement
A move from one grid point to another has a direction that can be named. Going from (2, 2) to (4, 2), the across value grows while up stays the same, so the move is to the right: east. Going from (3, 1) to (3, 4) keeps across the same and increases up, which is north. Reading a movement as a direction joins grid references to the compass: the change in the numbers tells you which way you went. This is the skill behind giving directions on a map, where each leg of a journey is a move in a named direction.
Maps run on grid references
Bringing the unit together, a grid map gives every place an exact address as a grid reference, and movements between places are described by directions and pathway lengths. School at (2, 1), park at (4, 3), shop at (1, 4): each is fixed by two numbers, and getting from one to another is a matter of moving so many units in named directions. With points plotted and read, directions and turns understood, pathways followed and movements named, a child can both create and interpret a grid reference system — locating, describing and navigating positions, the practical geometry that maps, games and screens all depend on.