Every good map must have as many of the "Seven Key Elements of a Map" as possible. First, just like a story, a book, or a product you purchase in a store, a good map needs a title to quickly inform the map reader of what exactly they are observing. Tiles are usually a very short description or name of a map and found at or near the top of a map. Second, a map needs to list the author’s name, so we know who to praise if it is a good map and who to ridicule if it is a bad map. Third, every good map needs to display the date it was made. For example, in the lecture hall where I teach several Geography courses, there is a large world map on the wall that was made in 1975. This explains why many of today’s newly formed countries are not shown on the map, including the countries of South Sudan, Eritrea, and Croatia, among many other countries formed since the date of the map’s projection. Therefore, the date is crucial to provide a chronological context of the map’s production. For any map that uses data, an identification or attribution of the source of that data is the fourth key element of a map. Just like any reference or citation a student would make in a research paper, a map maker must also cite their sources on the map.

The final three key elements of the map are arguably the most important to consider if/when you create your own map. The fifth key element is a north arrow or compass rose, which is simply a mark on a map that denotes the map's orientation and helps the map reader know which direction to hold their map.

For example, if one of Indy’s convention or sporting event tourists was given this accurate, albeit north arrow deficient map below, they would think the airport in Plainfield was on the northeast side of metropolitan Indianapolis and to get to their hotel in Carmel, they should travel to the Southside. Of course, those of you from or remotely familiar with Indianapolis know these are all incorrect descriptions of location and direction in Indianapolis. Carmel is a Northside suburb and the airport is on the western side of the downtown, Indiana University – Purdue University Indianapolis (IUPUI) campus area. A simple arrow designating north was pointing down or directly to the bottom, this map would be much more useful toward correctly identifying direction and location in metropolitan Indianapolis.
Upside Down

Now that a north arrow is visible, the map viewer can then properly align the map. (Photo by author)
Right side up

The sixth element of a map is a “key” one … every map should have a legend or key. This is separate box or list on a map that name or explain the symbols used in a map to represent different locations. For example, I have recreated a map that was sent to me when I was a groomsman in a wedding in Chicago. Having never visited this area of Chicago, the map was somewhat useful for me. After all, the map did have a north arrow, which nicely informed me that First Street is north of Second Street. Fortunately, the map also properly displayed a legend at the bottom, right-hand corner of the map. Instead of showing every single place on the map, the mapmaker highlighted the only two places that mattered for those visiting the wedding; first, where the wedding takes place and second, where the party takes place afterward. On the map, a red dot represents the location of the wedding and the blue dot shows the location of the reception.
Wedding map
A map with a legend in the blue box at the bottom, right-hand side and a north arrow on the left side. (Photo by author).

The scale is the seventh and final key element of a map and is most useful when traveling. A map scale shows the relationship between a distance depicted on a map and that same distance in reality on Earth’s surface. One problem with the wedding map above is that there is no scale shown, so I do not know how far the distance is to get to the reception after the wedding. Is the distance between Second Street and First Street just a few yards or several miles? This is not known and is crucial information for someone that has never visited this area before. Even worse, because I did not know how far the two locations were to each other, I was late and not able to help set up for the reception … bummer.

There are three types of scales that you are most likely to use or read on a map, each of which is shown in the image below. A graphic scale is the most common and visually displays a bar with the actual distances shown as well. A written scale, as the name implies, describes what the distance on the map (e.g., one inch) is equal to in terms of the actual distance on Earth’s surface (e.g., 20 miles). Finally, the representative fraction, which is rarely used on maps, shows the relationship between one of any unit on the map and one of that same unit on the ground. The unit on the map is always represented as a 1 on the left side of a colon, with the unit on the ground on the right side of the colon. For example, if the representative fraction shown on a map was “1:20,000,000,” then 1 centimeter on the map is equal to 20 million centimeters in reality. That also means that 1 foot on the map is equal to 20 million feet in reality.
Types of Scale
The three main types of scales commonly used with maps. (Graphic by author).

Below is a map I made in 2004 of all locations of NASCAR races that were planned for the 2005 season. This map contains all seven of the key elements of a map. Can you find and identify all seven on the map, including the type of scale used?
NASCAR 2005

In the map below, you will see the scale at the bottom. Using the scale found in the bottom, right corner, what is the straight-line distance (in miles) from Lucas Oil Stadium to the Indianapolis Motor Speedway?
IMS to Lucas Oil
Answer: 4.5 miles