Maps are the primary tools by which spatial relationships and geographic data are visualized. Maps therefore become important documents.
There are several key elements that should be included each time a map is created in order to aid the viewer in understanding the communications of that map and to document the source of the geographic information used.
What are the parts of a map?
Numbered below are descriptions of cartographic elements that are commonly found on a map layout. Some maps have all eight elements while other maps may only contain a few of them.
These eight possible map elements that make up the parts of a map are:
- data (or map) frame
- map legend
- map title
- north arrow
- map scale bar
- metadata (or map citation)
- border (or neatline)
- inset (or locator) map.
1. Data Frame
The data frame is the portion of the map that displays the data layers. This section is the most important and central focus of the map document.
In this map example, the data frame contains a map of the continental United States showing historical grassland areas. The data frame, is also referred to as the map frame, is where the actual map data is displayed.
2. Map Legend
The legend serves as the decoder for the symbology in the data frame. Therefore, it is also commonly known as the key.
Descriptions detailing any color schemes, symbology or categorization is defined here.
In the legend below, the grassland data has been categorized with different shades of green and yellow. The text of the legend describes what each color means.
Without the legend, the color scheme on the map would make no sense to the viewer. The legend tells the viewer that the darker the color, the more extreme the increase or decrease in years since a fire has occurred.
3. Map Title
The title is important because it instantly gives the viewer a succinct description of the subject matter of the map.
The title “Historic grasslands in the continental United States” quickly tells the viewer the subject matter and location of the data for that map.
4. North Arrow
The purpose of the north arrow is for map orientation.
This allows the viewer to determine the direction of the map as it relates to due north. Most maps tend to be oriented so that due north faces the top of the page.
There are exceptions to this and having the north arrow allows the viewer to know which direction the data is oriented.
To learn more about when to use a North Arrow, read “To North Arrow or Not to North Arrow“.
5. Map Scale
The map scale explains the relationship of the data frame extent to the real world. The description is a ratio. This can be shown either as a unit to unit or as one measurement to another measurement.
Therefore a scale showing a 1:10,000 scale means that every one paper map unit represents 10,000 real world units.
For example 1:10,000 in inches means that a measurement of one inch on the map equals 10,000 inches in real life.
The second method of depicting scale is a comparison with different unit types.
For example, 1″:100′ means that every inch measure on the paper map represents 100 feet in the real world.
This ratio is the same as 1:1200 (1 foot = 12 inches). In addition to text representation as described above, the ratio can be shown graphically in the form of a scale bar.
Maps that are not to scale tend have have a “N.T.S” notation which stands for “Not to scale.”
6. Map Citation
The citation portion of a map constitutes the metadata of the map.
This is the area where explanatory data about the data sources and currency, map projection information and any caveats can be added. In the example below, the citation tells the source of the data and who created the map.
Citations help the viewer determine the use of the map for their own purposes.
7. Map border
The purpose of a map border, also known as the neatline, is purely for aesthetic reasons. A map border can be used to serve as a visual containment for all the elements of a map.
On this map, the neatline is a simple black line that forms a box around the map elements.
8. Inset Map
The inset map is a smaller map that is shown to help provide geographic context to the map reader.
Inset maps can be used in two ways.
The first function of an inset map is to show a larger geographic area to show where the geographic subject of the map is located. This can be useful for showing where small geographic area located within a country or a state.
The second function of an inset map is to show an area of detail. When showing a small scale map, or a map that covers a large geographic area, sometimes areas of the map are hard to see. An inset map can show a zoomed in section of the larger map so that more of the detail of that area can be seen.
Watch: Parts of a map
Article first written: January 23, 2000. Last Updated: July 25, 2022.