Grid+Systems

Grid Patterns The most common way to locate a place on a map is to use a grid system. In this page, we'll look at two different grid systems.

Alphanumeric Grid The alphanumeric grid uses letters and numerals to identify squares in a grid pattern. An alphanumeric grid is often used on road maps. Grid squares are identified by a letter on one side of the map and a number on the other. This is the most basic grid system.

Activity Create a grid with the materials provided. Make sure the grid is marked A, B, C and 1, 2, 3 as discussed in class. Play a game of tic tac toe using the coordinates as your guide to place and find your pieces. Use small pieces of paper or something similar for play pieces. Play 3 rounds with one person, and then move on to the next.

Extension-make a larger version of tic tac toe!

Latitude and Longitude The second type of grid system divides the earth into a series of grid squares. No matter where you are in the world, your location can be identified by a latitude and longitude "address. "

If you use latitude and longitude, the geographic centre of the world is in the Gulf of Guinea, off the coast of West Africa. Check in your atlas and you will see that this is 0{degrees} latitude and 0{degrees} longitude. From here, a gridwork of lines extends north-south and east-west. Using this grid, you can determine the location of any place in the world as the intersection of a line of latitude and a line of longitude.

Latitude and longitude are measured as angles, with the center of each angle at the center of the globe. Latitude is measured north and south from the equator and longitude is measured east and west from the prime meridian.

Using Latitude and Longitude, you can find any single spot on the earth. It is an EXACT way of doing this, there are no two spots the same on the earth!