ggpolar full southern hemispheric plot only includes Antarctic main land

[thomas-muench]

In ggpolar(), when plotting the southern hemisphere over the full longitudinal range (pole = "S" and max.lon = 180, min.lon = -180, i.e. not plotting a segment), the map source only includes the Antarctic main land, since the map source is called from ggplot2::map_data("world", "Antarctica").

This behaviour is not documented and is unexpected at first sight when setting e.g. min.lon to some value in the tropics or subtropics.

The reason is that when we use the ggplot2::map_data("world") instead, the tropical and subtropical land areas of the southern hemisphere would be included but with political boundaries, which can't be switched off by the new function parameter plot.political.boundaries (#9). This would be inconsistent behaviour compared to north polar plots. Also, using the same new map data from #9 as for segments and the Northern hemisphere would result in the buggy line at 180W, which is most obvious and unpleasant for south polar plots.

All in all, the best solution at the moment is to keep the map source as is but to document the behaviour that only Antarctic main land will be plotted for full longitude south polar plots.

[thomas-muench]

Closed by #9.