GPS library toolkit to read and decode standard GPS NMEA 183 sentences from the RS232 serial port as well as compute great circle distances and bearings. Several C/C++ example programs with full source code are included. Features of the MarshallSoft GPS Component (MGC) include: * Uses the Windows Win32 API for serial port input. No special Windows driver is required. * Runs as a background thread unattended. * The most current GPS data is always available on demand. * Support functions (such as mgcGreatCircle) are included. * Most commonly used NMEA sentence types are automatically decoded. * Functions provided to read altitude, latitude, longitude, and sea level values as well as compute bearing, * Examples to decode GPRMC, GPGGA, GPGLL, and GPGSV sentences. * Can be called from any application program capable of calling the Windows Win32 API. The evaluation version of MGC4C is fully functional. Free technical support and updates for one year. Royalty free distribution.