Understanding Latitude and Longitude for APRS

APRSdos doesn't use the standard DD-MM-SS format directy. It uses a DDMM.MM format which is directly convertable from the DD-MM-SS by a simple dividing of the Seconds[SS] by 60. APRS only makes use of DEGREES and MINUTES in tact, and the SECONDS are only used in a decimal format. If you had an latitude of 42-38-55 and wanted to use this for APRSdos, then you would first write down the 42 and 38 together (like this: 4238). Then take the SECONDS (55) and divide it by 60 to obtain the decimal part of a minute (55 / 60 = .92 rounded to two places). Add this .92 to the 4238 you had written down, and you should have 4238.92 on your paper. Save this value for your latitude and use it to answer your location question in APRS. You will do the same thing for the Longitude. APRS windows version takes the values in DD-MM-SS.


If you have no idea what your latitude/longitude is, and you have a real street address (not a PO box) you should try a site called http://www.geocode.com/modules.php?name=TestDrive_Eagle . When you access this site, Enter your address and hit the "REQUEST" button. On the next page that loads, click on the "Show the results" button. Your lat/long will be shown in the NAD27 box below. Both DD-MM-SS.S and DD-MM.MMMM (round the .MMMM part to two places - .MM) versions of your lat/long are shown. APRSdos uses the data in the DDMM.MM format while Winaprs uses DD-MM-SS, so write both sets of numbers down and insert these into the program when asked for this information.

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created 12/26/97; last date of modification 03/21/06