This program allows both great-circle (polar) and
rectangular projections of the world. The
great-circle map is centered on any specified
latitude and longitude (the "home" location). The
rectangular projection is shown with the home
longitude in the middle of the screen.
The extensive database of cities and countries was
upgraded by Vince Grgic, S52CC, and thanks are
extended to him for his considerable effort! If you
have modified that database yourself, be sure to
archive it and add your changes to Vince's version.
Better yet, tell either of us about any changes so
they may be incorporated into the program.
- The home location can be
specified by either a direct entry into a textbox
or by using a pulldown list of over 3200 sites
around the world.
- Similarly, a target location can
be specified directly, by using another pulldown
list or by entry of the Maidenhead grid data into a
- The home and/or target locations
may also be entered by selecting the rectangular
projection and left-clicking on a location to
instantly specify a home location, or
right-clicking on a location to instantly specify a
new target location.
- The target location may be
entered on either the polar or rectangular
projection by clicking on List Calls and then
selecting a prefix.
- The current sun location along
with the terminator are (optionally) shown on both
projections. An Offset input allows correction for
daylight savings or half-hour time zone
- The path from the home location
to the target location is shown on both the polar
plot and the rectangular plot.
- Text data files for an antenna
pattern can be overlaid onto both the polar and the
rectangular plots; pattern size is adjustable.
"Rings" showing gain referred to the azimuth of
maximum transmission and 3, 6 and 12 dB below that
point can be toggled on and off.
- The size of the plot in terms of
kilometers can be stepped by pressing the "Closer"
or "Farther" buttons.
- A compass with lines at 10 degree
intervals can be overlaid on the display. This can
be toggled on and off using the "Compass"
- A set of rings showing distance
in 1000 km intervals can be overlaid on the
display. This too can be toggled, by using the
- The resolution of the on-screen
plots can be adjusted over a wide range. This
allows quick screen update even on a slow computer,
or higher-quality presentations at the expense of
an increase in plotting time. The output from the
printer is always at the highest resolution.
- The output to the printer is from
a separate routine which closely duplicates the
output as seen on the screen, but of course without
pixelation. To send a plot (polar or rectangular)
to the default printer just press the "Print"
- If the home location is within
the contiguous United States, and if the size is
set so that the map covers mostly those states,
then the map shows the state boundaries as
- On exiting the program the
current parameters are stored for an easy
- The plotting routines really need a
fast computer. Using a fast computer allows good
screen resolution within a reasonable time frame.
Slow computers take longer to re-plot the screen
for a given resolution. Plotting resolution is
adjustable over a wide range.