Click on each of the buttons in sequence to learn how to use a coordinate scale.

Place the 100,000 meter square identifier in front of the coordinate, UP255797.

To determine the correct two-letter 100,000 meter square identifier, look at the grid reference box in the margin of the map. You must look to see where the 00 lines falls in reference to your point on the map and use the identifier that is on the same side of the 00 line. With this example, your point is below the 00 grid line so the 100,000-meter square identifier is UP.

Slide the scale to the right, keeping the bottom of the scale on the bottom grid line until Point A is under the vertical (right-hand) scale. To determine the six-digit coordinate, the 100-meter mark on the bottom scale, which is nearest the vertical grid line, is the third digit of the number 255. The 100-meter mark on the vertical scale, which is nearest Point A, is the sixth digit of the number 797. Putting these together, you have 255797.

Check to see that the zeros of the coordinate scale are in the lower left-hand (southwest) corner of the grid square where Point A is located.

Place a coordinate scale on the bottom horizontal grid line of the grid square containing Point A to determine the third and sixth digits of the coordinate.

The number of the horizontal grid line on the bottom (south) side of the grid square gives the fourth and fifth digits of the coordinate.

The number of the vertical grid line on the left (west) side of the grid square gives the first and second digits of the coordinate.

Locate the grid square in which the point is located (see Point A).