GreatCircle Application for the Palm OS
Version 2.0*


Main GreatCircle Display GreatCircle is an application for Palm OS based handhelds to compute the great circle distance between two locations on the Earth. It also displays the great circle bearing angle from one location to the other.

GreatCircle can be used in conjunction with the GeoDB database application. You can think of GreatCircle as the computation engine and GeoDB holds the location information. However, as of Version 2.0, you can input locations manually.

If you do not have GeoDB installed in your handheld you may also want to install the GeoDB application available here

GreatCircle displays the following data:

We hope you find GreatCircle a useful adjunct to your Palm applications.


The archive file includes:
The executable file to be installed in your Palm.
The required mathematics library -- V1.1
This file -- gc.html
gcmain.gif, gcmenu1.gif, gcmenu2.gif, gcmenu3.gif, gcempty.gif
Images for gc.html
To install GreatCircle open the file and use your Palm installer to install gc20.prc.
Great Circle requires the included MathLib.prc*. If you already have MathLib.prc installed you do not need to install it.

If you do not have GeoDB you should install it. It will make input of location data much easier. To do this download, read the geodb.html documentation with your internet browser and install GeoDB accordingly.

The included MathLib.prc is the latest version (V1.1 dated 4/14/1999). You may update with this one if you desire.

GreatCircle will be placed in the 'unfiled' category. You may move it to any category.

Using the Application

GreatCircle empty main display When you first open GreatCircle the main screen has no data locations defined.
You will see four data headings as shown on the right. You will also see the name of the active GeoDB database in the upper right (if you have installed it). Once both the 'From:' and 'To:' locations are defined, the distance and bearing are computed.

Other controls are available in the 'Data' and 'Units' menus, discussed next.

Data Menu

The two items are: GreatCicle Database... Menu GreatCicle Select Database Menu

Units Menu

The units choices are: GreatCicle Units Menu Tapping the desired unit name will immediately return to the main display with the data in the selected unit.

Contact Info

GreatCircle was created by David W. Bray, Potsdam, NY;
Copyright © 1999-2004 David W. Bray, All Rights Reserved.

The Bray Palm OS Page can be found at:


GreatCircle is freeware no registration is required. We hope you enjoy using it.

This archive may be freely redistributed, provided it is made available only in its complete, unmodified form with no additional files and for noncommercial purposes only.
Any other use must have prior written authorization from David W. Bray.

Unauthorized commercial use includes, but is not limited to:


This program is provided without warranty and the user accepts full responsibility for any damages, direct, indirect, incidental, consequential, special or exemplary damages or lost profit resulting from any use or misuse of this application.

Foot Notes

* Many thanks to Rick Huebner, the author of MathLib, for his excellent routines and making them freely available.

*Program Changes in Version 2.0

Version 1.2 Bld:307 is the original release.
  1. Added dummy button for refresh in OS5 (V1.2 Bld:308)
  2. Added 'Find' button (V1.2 Bld:309)
  3. Added 'Database' menu item to allow selection of GeoDB databases. (V1.3 Bld:315)
  4. Changes to improve OS4 compatibility (V1.3 Bld:316)
  5. Changed internal data structure to allow From/To locations to be in different databases. (V2.0 Bld:404)
  6. Changed the algorithm for more accuracy, thereby allowing very small distances to be displayed. (V2.0 Bld:404)
  7. Added "Pen" (manual) location input. (V2.0 Bld:404)
  8. Added Feet, and Meters to the Units menu. (V2.0 Bld:404)
  9. Added selection of result precision. (V2.0 Bld:404)
Future releases will change the version number only for major changes. All changes will have an increasing Bld: (build) number.
To be sure that your version is up-to-date a check the Bld: number shown in the 'About' screen.

The current Bld: is 404.