Note that these samples have been converted to the ANSI/ISO character set used for most web documents. Simple cut and paste of the samples into a Microsoft Windows text editor (such as Notepad) will result in a file in the wrong character set for a DOS application. In particular the degree symbols will need to be converted from the ANSI representation (0xB0) to the IBM "OEM" character set representation (0xF8).
The white arrowed lines show my aerotow departure from the airfield followed, a few hours later, by my return via a circuit which was rather extended to ensure recording a point in sector for the use of BOO as a finish point - without an incursion into the power circuit to the north-west of runway 25.
The magenta airspace lines mark parts of the London Terminal Control Zone and come from a different map file. Similarly, the point BOO is a BGA (British Gliding Association) standard turn point and so also comes from another map file.
BOOF1L and BOOF1R define the left and right ends of finish line one, used for finishers from the south west. Similarly, BOOF2L and BOOF2R define the other finish line. BOOF1L and BOOF2R have the same physical position.
DUCKP is a local start point (the duck pond in the nearby village of Lane End) sometimes used in preference to the BGA start points in the vicinity because it is close to the airfield but clear of airspace.