Directional indicators on maps come in many forms and serve a variety of purposes, from general orientation for the casual user to the facilitation of actual navigation by compass. Others are simply intended to be decorative.
Some take the form of an elaborate compass rose - the compass face with which most people are familiar - while others are little more than an arrow indicating north on the map. Nautical charts often feature very precise compass roses which are marked with a full 360° and show both true north and magnetic north, while maps intended to help people find their way through a network of roads don’t require indicators with that much information. Maps which are created to entertain as much as they are to orient - whimsical tourist maps, for example - may include directional indicators strictly as design elements.
The evolution of the compass rose is an interesting story of its own. In the early days of navigation, the cardinal directions (north, south, east and west) were referred to by the names then associated with the prevailing winds which blew from those directions; in fact, the symbol on maps of the time was known as a “wind rose”.
The first wind roses began appearing on maps in the 14th century, and featured up to 32 separate wind directions: eight major winds, eight half-winds and 16 quarter-winds. These 32 discrete directions are still used today, with modern names all derived from the cardinal directions, e.g. northeast, north-northeast, northeast by east, etc.
For most applications, all that is required from a directional indicator is to let the map user know which side of the map corresponds to north. By modern convention, this is generally the top of the map, but a simple arrow on the map can confirm that. For stylistic reasons the arrow will often be more than just a north indicator - it may include less prominent east and west indicators, for example - but these are essentially vestigial.
Directional Indicators as Design Elements
In some cases, the directional indicator on a map might be as much a design element as it is a functional feature. Many maps are not intended to be used for actual navigation, but rather to provide a schematic of a place. A zoo, for instance, or a subway system, or a tourist map of a region only meant to give a general sense of which attractions are near each other.
Peter Crandall - Digitization Lab Assistant, Stanford Libraries.
Initially brought on to help shepherd maps through the digitization process, over the past few years the scope of my work has expanded to include working with books, player piano rolls and the odd bit of code. Always fascinated by maps, I've really appreciated the opportunity to get hands-on experience with Stanford's remarkable collection of unique and rare materials.