While there are several formats for writing latitude and longitude that the 3TIER website will accept as a search query, the recommended formats are either a street address or in decimal degrees. See examples below:

Street address: 2001 6th Ave, Seattle, WA 98121
Decimal degrees (lat, lon): 46.006, -118.744

3TIER utilizes decimal degrees because they are the most convenient format for calculation and computation purposes. As with other formats, the convention is that latitude is written first, and longitude is second. For example, the latitude and longitude of Seattle, WA in decimal degrees is 47.621, -122.347.

A value in decimal degrees to 4 decimal places is accurate to 11.1 meters (+/- 5.55 m) at the equator. A value to 5 decimal places is accurate to 1.11 meters at the equator. As with any data entry, it is important that you double check with the map to make sure that the coordinates you enter make sense, and you did not mistakenly enter a number or switch a digit by mistake.

Conversion to Decimal Degrees

If you only know your location in degrees:minutes:seconds, use this simple formula to convert your location into decimal degrees:

Decimal Degrees = Degrees + minutes/60 + seconds/3600

For example, a degrees:minutes:seconds value of "38° 53' 23" N, 77° 00' 32" W" converts to the decimal degree value of "38.88972°, -77.00889°" like this:

NOTE: Positive latitudes are north of the equator; negative latitudes are south of the equator. Positive longitudes are east of the Prime Meridian; negative longitudes are west of the Prime Meridian.