Praxis Geography (5921)

A map is a two-dimensional representation of all or part of Earth's surface. Maps serve as fundamental tools for geographers, allowing them to display spatial information, analyze geographic patterns, and communicate location-based data. Maps differ from the actual landscape they represent because they are selective, showing only chosen features, and they use symbols to represent real-world objects.

Maps possess several essential properties that determine their usefulness. Scale refers to the ratio between distance on the map and actual distance on Earth's surface. A large-scale map shows a small area with great detail, such as a city street map. A small-scale map shows a large area with less detail, such as a world map. Scale can be expressed as a representative fraction (1:24,000), a verbal scale (one inch equals one mile), or a graphic scale (a bar showing distances).

Direction on maps is typically indicated with north at the top, though this convention is not universal. Maps include directional indicators such as north arrows or compass roses. The four cardinal directions are north, south, east, and west. Intermediate directions include northeast, northwest, southeast, and southwest.

Location on maps can be expressed in absolute or relative terms. Absolute location uses a coordinate system, most commonly latitude and longitude. Latitude measures distance north or south of the equator in degrees, ranging from 0 degrees at the equator to 90 degrees at the poles. Longitude measures distance east or west of the Prime Meridian, ranging from 0 degrees at Greenwich, England, to 180 degrees at the International Date Line. Relative location describes where a place is in relation to other places or features.

Reference maps emphasize the location of spatial phenomena. These include political maps showing boundaries and cities, physical maps showing landforms and water bodies, and road maps showing transportation networks. Reference maps prioritize accuracy of location over thematic content.

Thematic maps emphasize the spatial distribution of one or more geographic attributes. Choropleth maps use colors or shading patterns to represent data values for predefined areas such as states or counties. Isoline maps connect points of equal value with lines, commonly used for elevation (contour maps), temperature (isotherms), and atmospheric pressure (isobars). Dot maps use dots to represent the occurrence or quantity of a phenomenon. Proportional symbol maps use symbols of varying sizes to represent quantities. Flow maps use lines of varying thickness to show movement between places.

Topographic maps are detailed reference maps showing both natural and human-made features. They use contour lines to represent elevation, with each contour line connecting points of equal elevation. The contour interval is the vertical distance between adjacent contour lines. Closely spaced contour lines indicate steep terrain, while widely spaced lines indicate gentle slopes. Topographic maps include symbols for roads, buildings, vegetation, water features, and boundaries.

A globe is a three-dimensional scale model of Earth. Globes provide the most accurate representation of Earth because they maintain correct relationships between size, shape, distance, and direction. However, globes are impractical for many purposes because they cannot show much detail and are difficult to carry and store.

Globes accurately represent the graticule, the network of latitude and longitude lines. On a globe, lines of latitude (parallels) are parallel circles that decrease in circumference from the equator toward the poles. Lines of longitude (meridians) are half-circles that converge at the poles. The intersection of latitude and longitude lines creates a grid that allows precise location identification.

The equator divides Earth into the Northern and Southern Hemispheres. The Prime Meridian and the 180-degree meridian divide Earth into the Eastern and Western Hemispheres. Important latitude lines include the Tropic of Cancer (23.5 degrees north), the Tropic of Capricorn (23.5 degrees south), the Arctic Circle (66.5 degrees north), and the Antarctic Circle (66.5 degrees south). These lines mark significant boundaries related to Earth's relationship with the sun.

The fundamental difference between maps and globes relates to dimensionality. Globes preserve the spherical nature of Earth, maintaining accurate spatial relationships. Maps require transforming the curved surface of Earth onto a flat surface, which inevitably introduces distortion.

Globes excel at showing the entire Earth or large portions of it with minimal distortion. They accurately represent the relative size and shape of continents and oceans. Globes demonstrate geographic concepts such as great circles (the shortest path between two points on a sphere), time zones, and the tilt of Earth's axis.

Maps offer advantages of portability, the ability to show various scales, and the capacity to display thematic information effectively. Maps allow cartographers to focus on specific areas or themes while excluding irrelevant information. Maps can be reproduced easily and inexpensively, making them accessible for widespread use.

Effective maps include several standard elements. The title identifies the subject and geographic area covered. The legend or key explains the symbols used on the map. The scale indicates the relationship between map distance and actual distance. A north arrow or compass rose shows orientation. The source identifies where the data originated. The date indicates when the map was created or when the data was collected.

Additional elements may include an inset map showing the location of the mapped area within a larger context, a locator map indicating the position of the main map area, and a graticule showing latitude and longitude lines. Some maps include an index for locating specific features.