An Earth's Magnetic Field Calculator for the Palm OS

MagCalc is a Palm OS program for computing the Earth's magnetic field at any location based on the US DoD magnetic field model. MagCalc computes the total intensity, horizontal intensity, magnetic declination (or variation) and dip. It also computes the annular rate of change of each these parameters. These calculations are performed based on user entered latitude, longitude, altitude above sea level and date.

System Requirements:

MagCalc runs under Palm OS 2.0 or later. MagCalc needs MathLib.prc to be installed on the same Palm as MagCalc. MathLib is a widely used library of mathematical routines. MagCalc should work with any version of MathLib that is installed on your Palm.

Instructions:

The latitude an longitude fields accept any of the following formats: decimal degrees (e.g. 39.1636°); degree and decimal minutes (e.g. 39° 09.187'); or degrees, minutes and decimal seconds (e.g. 39° 09' 49.1"). Note that the formatting does not matter, the numbers in each field can be separated by any non-numeric characters. The first number is always interpreted as degrees, the optional second number is interpreted as minutes, and the optional third number is interpreted as seconds. Thus 39° 09' 49.1" is identical to 39 9 49.1, the latter being much easier to write.

The current date is automatically filled in, although you can easily select a different date. Dates are only entered as decimal year format, but the calendar widget is available for easily selecting a particular date. The model is only designed to support the period from 2000 to 2005, but the program will, under protest, compute any other date you chose to enter.

A help menu is available to provide some tips for using MagCalc.

Cut and paste work into and out of other applications.

The magnetic field calculations are based on the geomag model with the US DoD WMM model coefficients. See http://www.ngdc.noaa.gov/seg/WMM/DoDWMM.shtml for more information.

Download the MagCalc application (v1.4) for Palm OS in Zip format or Stuffit format

MagCalc was developed using CodeWarrior for the Palm OS Version 8.0. The complete source code can be downloaded as a Zip file for use on Windows boxes or a Stuffit file for use on the Macintosh. The source code and program are provided without any warranty of any kind.

Download the MagCalc source code (v1.4) for Palm OS in Zip format or Stuffit format

Please send bug reports to me at the address below. I am not an expert in general Palm programming, so please don't ask me any Palm programming questions.

Revision History:

Version 1.4 - released 31 Mar 2005: Updated to save and restore state of N/S and E/W buttons.

Version 1.3 - released 04 Jan 2005: Updated to support period from 2005 to 2010 using updated DoD model.

Version 1.2 - released 01 Oct 2002: First released version. Web site updated on June 6, 2003 to replace defective Zip files.