Maps come in an infinite variety of sizes and styles and serve a limitless diversity of purposes. Regardless of type, however, every map should contain a few basic components to facilitate its use Omission of any of these essential components decreases the clarity of the map and may make it more difficult to interpret.
- Title: This should be a brief summary of the map’s content or purpose. It should identify the area covered and provide some indication of content, such as “Road Map of Kenya,” or “River Discharge in Northern Europe.”
- Date: This should indicate the time span over which the information was collected. In addition, some maps also give the date of publication of the map. Most maps depict conditions or patterns that are temporary or even momentary. For a map to be meaningful, therefore, the reader must be informed when the data were gathered, as this information indicates how timely or out of date the map is.
- Location: Although the grid system of latitude and longitude is the most common system of location seen on maps, other types of reference grids may also be used on maps. For example, some large-scale maps (such as road maps) use a simple x- and y-coordinate grid to locating features (similar to that shown in Figure 1-11), and some maps display more than one coordinate system.
- Legend: Most maps use symbols, colors, shadings, or other devices to represent features or the amount, degree, or proportion of some quantity. Some symbols are self-explanatory, but it is usually necessary to include a legend box in a corner of the map to explain the symbolization.
- Scale: Any map that serves as more than a pictogram must be drawn to scale, at least approximately. A graphic, verbal, or fractional scale is, therefore, necessary.
- ORIENTATION:a map should indicate which way is north (and/or south, east and west). Commonly this is done by a north arrow or compass rose. Orientation may also be shown by graticule or grid marks (e.g. lines of latitude and longitude). By convention north is towards the top of the page (thus some maps do not have north arrows), but the orientation must still be given for a ‘proper’ map. North does not have to be at the top of the page and a north arrow is essential in maps where it is not.
- Data Source: For most thematic maps, it is useful to indicate the source of the data.
- Projection Type: On many maps, particularly small-scale ones, the type of map projection is indicated to help the user assess the kinds of distortions on the map.
- BORDER(s): a border identifies exactly where the mapped area stops. The border is often the thickest line on the map and should be close to the edges of the mapped area. The distance between the map and the border should be the same on all sides (balanced).
There can also be a border around the entire map layout (enclosing and grouping the title, legend, text boxes, etc.). Both of these borders are sometimes referred to as a ‘neatline.’ In addition, there is sometimes a thin additional line just outside of a border (accentuating it and ideally making it more visually appealing) that may also be referred to as a neatline.
- PURPOSE: All maps have a purpose which should influence every element of the map and the map layout. A cartographer should be able to clearly articulate the purpose of their map and should keep the audience and the client in mind.