Description

To use this version of GreatCircle you must install a Ewe¹ VM (Virtual Machine) on your computer. Ewe is a version of Java which runs on a variety of desktop and handheld computers. It is very compact and efficient. It uses only about 2 Mbytes of memory.
To learn more about Ewe please read the introduction on the Bray Mobile Applications page.

GreatCircle displays the following data:

• Latitude and longitude of two Earth locations -- selected from Location Data CSV files and/or entered manually.
• The great circle distance between the locations in either: kilometers, nautical miles, statute miles, meters or feet.
• The great circle bearing angle in either: degrees or grads, from the 'From' locations to the 'To' location.

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

Installation

The first thing to do is to install the Ewe VM on your computer(s), if not already installed.
Follow the instruction found on the Ewe Download and Installation Page for your computer(s). The Ewe installer will create directories on your computer and put the Ewe VM files in them. After Ewe is installed find the Ewe directory. For example, in a Windows Desktop it will be where you told the installer to install it, and in the Pocket PC it will (probably) be in \Windows\StartMenu\Programs\Ewe.

There is no installer for GreatCircle.ewe. The files in the greatcircle10Install.zip archive can be put in any directory of your choice. However it is recommended that you put them in the directory with the Ewe VM. Specifically the directory in which you find 'ewe.ewe'. This will make it easier to find them if you want to change them, and when you add additional applications from Bray Mobile Applications, common files can be shared. Specifically the Location Data CSV files.

So once you find the proper directory copy all of the files in greatcircle10Install.zip into that directory, in what ever manner you do that on your computer.

Note: No matter what Regional settings are used on your computer(s), GreatCircle always uses the '.' (period) as the decimal point, the ':' (colon) as the hour/minute/second separator, and the ',' (comma) as the data separator.

GreatCircle should be ready to run now. Find GreatCircle.ewe with your File Explorer, click on it to try it out!

Using the Application

The Menu Buttons are discussed last below.

Controls -- Top Buttons

The From and To buttons popup a Location Form for entering location data manually, as show to the right. Enter the desired data for the Name (optional), Latitude and Longitude and set their direction from Greenwich or the Equator using the pull-down selectors.

The input for latitude and longitude may be in any of the following three formats:

degree ':' minute ':' second '.' decimal second	44:38:33.72
degree ':' minute '.' decimal minute	44:38.562
degree '.' decimal degree	44.6427

The only allowable input characters are: digits, '.' (period) and ':' (colon). (Remember the decimal point is always the '.').
All three of the above example formats have the same latitude value.

Once both the From and To locations have been define the Distance and Bearing will be computed.

• Distance: This is the distance between the 'From' and 'To' locations in the desire units set using the Units menu, and with the numbers of decimal digits set using the Decimals menu.

• Bearing: This is the great circle bearing angle between the 'From' and 'To' locations, respectively, in the desire units. North is 0 degrees (0 grads) and rotates clockwise. East is 90 degrees (100 grads), etc.

• Main This button restores the main display once Locations has been selected.

• Locations This button brings up a 'File Chooser' for selection of the desired Location Data CSV file (files with the extension of .csv). Once the file is chosen all locations in this file are displayed.
  Select a location by tapping a location data line to highlight it. The tap will bring up a selection box so that it can be designated to be a 'From' or 'To' location.
  Once you are done selecting location(s), tap the Main button to compute the Distance and Bearing.

See Supplied Location Data and About Locations Data below for more information.

Menu Instructions

• Decimals This allows the selection of the number of decimal digits used to display both Distance and Bearing.
  The choices are: 0, 1, 2, 3, or 4.

• Units The choices are:
  • Kilometers -- Display distance in kilometers (km).
  • Naut. Miles -- Display distance in nautical miles (nm).
  • Miles -- Display distance in statute miles (mi).
  • Meters -- Display distance in meters (m).
  • Feet -- Display distance in feet (ft).
  • Degrees -- Display great circle bearing angle in degrees.
  • Grads -- Display great circle bearing angle in grads. (There are 100 grads and 90 degrees in a right angle.)
  Tapping the desired unit name will immediately return to the main display with the data in the selected unit.

• Database When the Change menu item is selected, the next time Locations is tapped the File Chooser will be displayed so that a new Location Data CSV file can be chosen. This allows locations to be found in different Location Data CSV files.
  Using this you can select the From and To from different Location Data CSV files.

• Help
  • About This is the usual About information. It tells you the version of GreatCircle you have installed. Be sure to check the Bld: number to see that your GreatCircle is up-to-date.
  • Quit The obvious Quit selection. You can also quit using the upper right hand X. However, only the Quit button saves the current settings of GreatCircle for next usage start-up. If you stop GreatCircle using the Quit menu item, it will start-up with the current locations, units, and decimal settings.

More Details

Supplied Location Data

The Location Data CSV Editor Application (LocEdit) is available at the Bray Mobile Applications page. LocEdit makes it easier to edit Location Data CSV files and more data is available. If you are intending to create your own personal Location Data CSV files it is recommended that you get LocEdit.

Documentation that come with LocEdit has full details about a Location Data CSV file format.

The format of Location Data files is described next.

NOTE: Beware that CSV files are an acceptable format for Excel. However, DO NOT use Excel to create or edit them since all the latitude, longitude formats are not known to Excel and it will modify them incorrectly without giving an error message!

About Location Data