Map

I

Introduction

Map, representation of a geographical area, usually a portion of the Earth’s surface, printed and displayed on a flat surface. In most instances a map is a diagrammatic rather than a pictorial representation of the terrain; it usually contains a number of generally accepted symbols that indicate the various natural, artificial, or cultural features of the area it covers. The analogue hand-drawn map is now replaced by computer-drawn maps using a digital database. The database holds information about cultural and physical features in the environment, together with their descriptive details including location, name, classification, and further metadata. Maps produced from such a database can be displayed on a variety of modern media including paper, computer screen, mobile phone, in-vehicle navigation display, and the World Wide Web. The development of maps in different times and cultures—the history of cartography—is detailed in the article of that title.

II

Types of Map

Maps may be used for a variety of purposes, and as a result a number of specialized types of map have been developed.

A

Topographic Maps

The basic type of map used to represent land areas is the topographic map. Such maps show the natural features of the area covered as well as certain artificial features, known as cultural features. Political boundaries, such as the limits of towns, countries, and states, are also shown. Because of the great variety of information included on them, topographic maps are most often used as general reference maps or selectively as a base for special-purpose information. These maps at large scales normally form the basic mapping for a country or state. The majority of other maps from medium to small scales are then “derived” from these with the addition of further data and information.

B

Special-Purpose, or Thematic, Maps

Among the most important of the special-purpose maps are those used for navigation. On sea and in the air they are known as charts. Hydrographic and aviation charts are today produced in both digital and paper format. Hydrographic charts provide coverage of the oceans and other large bodies of water and their shores at a range of scales which indicate different levels of information detail. Over the water portion of a chart, depth in metres at low tide, dredged channels, buoys, lighthouses, and near-surface features, such as cables, pipelines, fish farms, and military training areas, are clearly marked. Onshore structures are shown but purposely limited to conspicuous landmarks and buildings (useful for visual navigation). Aviation charts for use over land somewhat resemble topographic maps but bear in addition the location of radio beacons, air corridors, and radio station ranges and coverage.

Statistical thematic maps use graphic symbols to illustrate quantity applied to point, line, or area features such as population age structure of towns, traffic flow on roads, crop and land use patterns, or percentage of adults visiting museums by local authority area.

Geological, political, environmental, and numerous other kinds of social and scientific data complete the array of special-purpose maps.