Converting Coordinates to Decimal Degrees

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Coordinates and Active911

Active911 uses latitude and longitude in decimal degrees and the WGS84 datum. To accurately capture and import map data into Active911, you need to make sure your data is in this format.

Almost all GPS units allow you to select the datum and coordinate format. If your coordinates are in a format other than decimal degrees, you will need to convert them to decimal degrees. The following formula can be used to convert minutes and seconds to decimal degrees.

Decimal degrees = Degrees + Minutes/60 + Seconds/3600

For those who are new to this process, You can open your data in MS Excel, Calc, or what ever spreadsheet editor you prefer. Transform the data to return degrees, minutes, and seconds in their own column, typically using a test to column tool. Now just replace the words 'Degrees', 'Minutes', and 'Seconds' with the corresponding cells numbers and put this formula into columns for latitude and longitude to the right of your existing data and copy down. You need to do this for both latitude and longitude. The two resulting columns will have your data in the decimal degrees that Active911 uses. To double check, put a few coordinate pairs into Google Maps to see if they map correctly.

Remember that Western longitudes need to be negative since they are to the left of the prime meridian


For further information, see Geographic Coordinate Conversion.