GreatCirc

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. Anyone may download and install GreatCirc 2.0 to access the basic features free of charge. Registration and payment is only required to unlock the Advanced features of the program. The "great circle path" is the shortest direct route between two points on the earth's surface. Because the earth is a globe, the shortest path between any two points lies on a circle which is centred at the earth's core and passes around the surface of the world. Who's it for? 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, search & rescue missions, etc. And anyone with a general interest in distances between geographic points, or plotting their travels on a world map. Basic Features (Free) Great Circle Distance calculation: find the shortest distance and direction between two points. 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. View the Great Circle, Rhumb Line, or Coverage Area plotted on a world map, in equirectangular projection. Enter map points by typing their latitude & longitude coordinates, or by clicking on the world map, or choose map points from a built-in list of Major Cities. Advanced Features (requires Registration) Main Window View the world map in Mercator projection or Globe View. (requires DirectX). Zoom and move or rotate the world map or globe. Save the map image to file, complete with lines or coverage area. Save the calculation results to file in HTML or CSV format. Calculate the magnetic compass directions, in addition to the True azimuths. Choose map points from a user supplied list file. Batch Mode Window Load a batch of locations and paths from a user supplied text file. Plot multiple great circle lines and label locations on the flat world map. Load alternate map images. Save batch Great Circle Distance calculations in HTML or a CSV formats.