Ideally, most of the text that occurs on a map should be associated with its appropriate feature, the name "France" should be associated with the corresponding Country area feature, "Atlantic" with the corresponding Ocean area feature and "Watling Street" with the corresponding Road line feature. If the database is structured in this way, it would be possible to use the computer mouse to point to an area shown on the screen and ask "what is this called?". Alternatively, the user could ask to be shown France, and the computer could highlight that on the screen.
However, in some cases there is no clearly defined feature corresponding to a name. The most obvious example is a mountain range. One cannot ask for the Rocky Mountains to be highlighted because there is no clearly-defined boundary where the mountains stop.
To cater for this case, VPF includes a Text Primitive. This consists principally of a shape line, along which the letters of the text are positioned.
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