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Gunamoi Software

   GreatCirc - Main Features

GreatCirc Program


What's New in 3.1

Main Features

Screen Shots




GreatCirc is a tool for calculating Great Circle distances on the earth's surface, and plotting points and great circle paths on a world map. 
(click here to see some screen shots)

Anyone may download and install GreatCirc to access the Lite features free of charge. 
Registration and payment is only required to unlock the Pro features of the program. 

Who's it for?

  • Navigators, of ships or aircraft, who want a quick indication of Great Circle or Rhumb Line path and distance.
  • Ham radio amateurs, to calculate antenna pointing for the most direct radio path.
  • Muslims calculating the praying direction (qibla) to Mecca.
  • Educators teaching principles of mapping or navigation.
  • Planners calculating coverage areas, for radio/radar systems, satellite spot beams, search & rescue missions, etc.
  • And anyone with a general interest in distances between geographic points.

Lite Features (Free)

  • Great Circle Distance calculation: find the shortest distance and direction between two points. (example)
  • Great Circle End Point calculation: find the end point of a great circle path, given start, distance and direction.
  • Rhumb Line Calculation: find the distance between two points along a line of constant bearing.
  • Coverage Area calculation: find a circular coverage area, given a central point and the radius. (example)
  • View the Great Circle, Rhumb Line, or Coverage Area plotted on a world map, in equi-rectangular projection.
  • Enter map points by typing their latitude & longitude coordinates, in decimal, or degrees,minutes,seconds format.
  • Enter map points by clicking on the world map.  Left-click for Point 1, right click for Point 2.
  • Choose map points from a built-in list of Major Cities.
  • Enter map points using Australian Map Grid (AMG) coordinates.
  • Perform calculations using a simple spherical earth model, or the WGS84 standard ellipsoid.

Pro Features (requires Registration)

Main Window

  • View the world map in Mercator projection or Globe View. (requires DirectX). (example)
  • Zoom the world map to get a closer look, or to more accurately click a location.
  • Move around the zoomed world map, or rotate the Globe view.
  • Save the map image, complete with lines or coverage area, to an image file (BMP, JPG, PNG, etc).
  • Save the calculation results to a PDF Report file, a HTML Report file, or to a comma separated text file for loading into a spreadsheet.
  • Save the Great Circle path, Rhumb line, or Coverage circle as a list of latitude & longitude points in a KML file for use with Google Earth.
  • Calculate and display the magnetic azimuths (compass directions), in addition to the True azimuths.
  • Choose map points from a user supplied file (including *.txt, *.csv, *.kml, *.gpx, or *.maplist file formats).
  • Save a Batch Report of Great Circle Distance calculations in a PDF Report file, a HTML Report file, or to a csv file for loading into a spreadsheet. (example)

Note that since version 3.0, the Batch Mode map plotting function of GreatCirc has been removed.  This previous Pro feature of GreatCirc is now available in the free Lite version of our MapList-Flat and MapList-Globe apps.  However, the ability to produce a Batch Report of Great Circle calculations for multiple locations is still available in GreatCirc via the File menu.