This is standard, though there are a number of different graphical conventions in showing them.
In the polar regions, a different convention is used.
There will be three different conventions, each hosted on a separate date.
For technical reasons, maps in the Encyclopedia follow different conventions.
Fandoms in other parts of the world have different conventions.
Older sources, particularly botanical works published before the 1950s, use a different convention.
Therefore the objectives of the different conventions must always be kept in mind and weighed against each other.
The reasons for such different conventions must then be sought in the social context.
The names given to comets have followed several different conventions over the past two centuries.
These different conventions differ by elementary terms that are positive real numbers.