[aprssig] APRS LAT/LONG standards

Curt, WE7U archer at eskimo.com
Thu May 26 14:23:45 EDT 2005

On Thu, 26 May 2005, Lee wrote:

> Here's what I use to allow easy and flexible entry of lat/long values:
>  Three fields that allow decimal values to be entered; one for degrees, one
> for minutes, and one for seconds. With this setup, those that need/want to
> enter the lat/long using degrees and decimal minutes simply enter the whole
> number degrees in the first field, the decimal degrees in the second field,
> and leave the third empty. If someone needs to enter degrees, minutes, and
> seconds they use all three fields. For someone to enter decimal degrees,
> they just use the first field.
>  All the work validating and converting is handled for the user and there's
> no need for them to perform any conversions. Simple instructions are all
> that is needed.
> A similar configuration can be used to display lat/long in different
> formats. This could default to a standard, and still offer the option to
> display in other formats as needed.

Xastir does it a bit differently, but tries to make it simple as
well.  Three input fields are used:

    UTM Zone
    Latitude or UTM Easting
    Longitude or UTM Northing

If you're doing  lat/long formats you skip the first field.  The
other two fields are basically free-form.  The software takes clues
from the entered string in order to determine what format it is in.
Put spaces between the different pieces and it figures it out.

Don't know any of the formats?  Hit the "Calculate" button with
empty or incorrect fields and it gives you a helpful message with
the possible input formats:

  **       Sorry, your input was not recognized!        **
  **   Please use one of the following input formats:   **
  ** 47.99999N  121.99999W,   47 59.999N   121 59.999W  **
  ** 10T  0574599  5316887,   47 59 59.9N  121 59 59.9W **

The calculator also understands +/- instead of N/S or E/W, so no
matter what format you use to enter the number you can get
reasonable answers.

Normal output would look like this:

               Decimal Degrees:  48.00093N   121.99993W
       Degrees/Decimal Minutes:  48 00.056N  121 59.996W
  Degrees/Minutes/Dec. Seconds:  48 00 03.3N 121 59 59.7W
 Universal Transverse Mercator:  10T  0574599  5316887
Military Grid Reference System:  10U EU 74599    16886
       Maidenhead Grid Locator:  CN98aa

Hit the "OK" button:  The calculator goes away and the coordinate
gets used in the input field for you station or an object/item.  If
you brought up the coordinate calculator from another dialog via a
"Calc" button that is.

Curt, WE7U.   APRS Client Comparisons: http://www.eskimo.com/~archer
"Lotto:    A tax on people who are bad at math." -- unknown
"Windows:  Microsoft's tax on computer illiterates." -- WE7U
"The world DOES revolve around me:  I picked the coordinate system!"

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