Mapping

Map scales
M_Map usually scales the map so that it fits exactly within the current axes. If
you just want a nice picture (which is mostly the case) then this is exactly what
you need. On the other hand, sometimes you want to print things out at some
exact scale (i.e. if you really much prefer sitting at your desk with a ruler and a
piece of paper trying to figure out how far apart Bangkok and Tokyo are). Use
the m_scale primitive for this - for a 1:250000 map, call
m_scale(250000);
after you have drawn everything (Be careful - a 1:250000 map of the world is a
lot bigger than 8.5"x11" sheet of paper).
This option is usually only useful for large-scale maps, (i.e. maps of very small
areas).
If you wish to know the current scale, calling m_scale without any parameters
will calculate and return that value.
To return to the default scaling call m_scale('auto').
(PS - If you do want to find distances from Bangkok to anywhere, plot an
azimuthal equidistant projection of the world centered on Bangkok (13 44'N,
100 30'E), and choose a fairly small scale, like 1:200,000,000). Another option
would be to use range rings, see example 11.