We said Tookeron campground lies 480200m east of somewhere and 6895900m north of somewhere. Look at Figure 1 again and you can see that S-E Queensland lies in 56J. By dividing the area between latitudes 80°S and 80°N into zones 8° wide, we get 20 divisions identified by letters of the alphabet (Reading south to north and omitting A,B,I,O,Y and Z.) Thus, each part of the grid can be identified by reference to these two scales. These are numbered 1-60 starting at the 180° meridian (Basically, the international date line). By dividing the circumference of the world (360°) by 60, we end up with 60 zones, each 6° wide. A universal transverse mercator (UTM) map of the world would end up looking like Figure 1. One method of representing the surface of a sphere on a flat piece of paper involves using a transverse mercator projection. This looks almost identical to the title of this article. So the “6” figure grid reference (GR) for Tookeron campground becomes 480200 6895900. This shows that the grid line (easting) numbered 80 on the Kooralbyn map, is really numbered 480 000m east of somewhere, and the northing numbered 95 is really 6 895 000m north of somewhere. Eight figure grid references (lines 10m apart) are rarely used because of the impracticality of estimating such small distances on maps.įrom where to these numbers come? Look at the bottom left corner of any topographic map and you will see that the numbers on the grid lines are part of a larger number. By subdividing the grid square further (lines 100m apart), we can get a more accurate description of the location of the campground as 802959. Thus, Tookeron campground is located in grid square (GS) 8095. The squares formed on the map can be identified by reference to the numbers on the lines that intersect in the SW corner of the square. The horizontal lines increase in magnitude as you read bottom to top (towards the north). The numbers on the vertical lines increase in magnitude as you read left to right (towards the east). These grid lines are 1000m apart and they are numbered in the margin, and sometimes within the map area as well. Topographic maps usually have a pattern of lines running north-wouth and east-west. The distance represented by 1 minute of longitude varies because lines of longitude are not parallel. And did you know that 1 minute of latitude = 1 nautical mile (1852m). Your choice! By the way, 60 seconds = 1 minute and 60 minutes = 1 degree. Most GPS will give you the option of expressing geographic coordinates in degrees, minutes and seconds, or degrees and minutes to the nearest 1/1000th of a minute, i.e.28☃.717’S,152☄7.900’E.

Thus, the geographic coordinates of Tookeron campsite are expressed as 28° 03’43”S,152☄7’54”E. The conventional method of describing the location of a place using geographic coordinates is to state the latitude first.

Lines of longitude are imaginary lines (meridians) running from pole to pole and they indicate the location of a place as so many degrees, minutes, and seconds east or west of the prime meridian (O°) which runs north-south through Greenwich in the UK. Lines of latitude are imaginary lines (circles) running parallel to the equator and they indicate the location of a place as so many degrees, minutes, and seconds north or south of the equator. What’s the difference and what should you use? Geographic Co-ordinates (latitude and longitude) Depending on what you tell your GPS to do, your position can be given in terms of latitude and longitude or as a grid reference. When should you use latitude and longitude or grid references for position fixes? Have you ever wondered what all those numbers and letters mean? Read on.Ī GPS is a magic tool to help you find your position on earth or to help you navigate your way around the bush.

Magic maps grid reference