How to Convert Latitude/Longitude to Grid Reference
If you have ever unsuccessfully attempted to flatten an orange peel, you've encountered the mapmaker's dilemma: displaying a sphere on a flat surface requires either distortion or a pair of scissors. Cartographers have addressed this problem with techniques called projections, the most familiar of which is the Universal Transverse Mercator (UTM) system. Instead of plotting latitude-longitude coordinates on a grid, the locations are mathematically converted to a reference grid of rectangular coordinates in meters.
Although the mathematics of conversion are quite complex, computer programs and websites that convert between latitude-longitude and a reference grid are widely available.
Instructions
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1
Obtain the latitude and longitude of the point of interest. The values may be expressed in either degrees-minutes-seconds (for example, 39° 17' 23.4") or decimal degrees (for example, 42.44543°).
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2
Enter the latitude-longitude pair in a computer program or website that provides the conversion and process (see References). By convention, west longitudes and south latitudes are negative numbers and east longitudes and north latitudes are positive.
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3
Read the grid reference position in X (east) and Y (north). Make a note of the UTM zone, which is needed to locate the point on a projected map.
