Up to this point in your life, you’ve probably looked at hundreds of maps, but it probably never critically critiqued one. While the perception of maps may be that they are neutral, infallible representations of reality, the truth is that all maps are created by cartographers who may make errors in design, or unintentionally, or intentionally, bias the map. It is a good exercise to look at a map, critically think about it, and then critique the map. In this section, we will critique a map, and then discuss its redesign.

This is a map that may be considered typical for someone who is new at making maps. Some of the undesirable characteristics of the map is because the map author chose not to change the default behavior of the mapping software. Other issues with the map are probably due to the map author not knowing any better. In either case, let’s look at the map and point out where the map design could be improved.

As the title is often the first thing a map user reads, and provides a concise description of the map, let’s examine that first. The current title the map is simply entitled population density. While at its core, the map is about population density, the title is still fairly vague. It doesn’t answer the question of when the population was that dense, and why we are only seeing the lower 48 states of United States. Why were Alaska and Hawaii left off the map? Additionally, the title is slightly off center. It would be much better if the title was centered on the top of the page.

Next, let’s focus on the North arrow. The North Arrow is way too large for this map. Remember, that items should be sized relative to their importance. The North arrow is not so important for this map that it needs to stand out that much. Additionally, assuming that the audience for this map would be Americans, the North arrow might not even be necessary since Americans are used to seeing United States, and having North be up on a map, making the north arrow redundant. If the North arrow is to be left on this map, it should be made considerably smaller, and placed out-of-the-way.

If we look right below the North arrow, we have the metadata showing the map author and the data source. There are two problems here. One, the text is too large. Map readers will look for the metadata if they want to see it, but it should not jump out this much. The font size should be reduced for the metadata. For the data source, ‘ESRI’ not very descriptive. It doesn’t tell us what year the data set was created, and a majority of map users would not be able to track down the original data source simply by ‘ESRI’.

Next let’s consider the scale bars. The scale bars have multiple problems. First, one of the scale bars represents the distance in decimal degrees. Decimal degrees is not a useful unit to measure distances on a map. I can’t think of the last time I have ever measured distance using decimal degrees. Second, the divisions and end points of the scale bars are not in meaningful, easy-to-use numbers. Instead of 0 to 32, why not 0 to 30? Instead of 0 to 2,840, why not 0 to 3,000? Using round numbers on your scale bars, make it easy for the map reader to scale distances. Third, the scale bars are too wide. The scale bars could easily be one third their width and be just as useful, and not so visually dominate the map. Remember, the scale bars in this map are not that important, and should be deemphasized so as to not attract the eye from the map body. Lastly, the scale bars are too tall. Again, having scale bars that large, the scale bars detract from the map too much, and are emphasized too much.

Next, let’s focus on the legend. As a matter of style, you should not title the legend with the word legend. Map readers know that this is the legend, and you could use that space better by replacing it with a descriptive title for the legend. One exception would be for, say, elementary schoolchildren who are not familiar with the components of a map yet and therefore need this instruction about what a legend is and looks like. Next, the description of the population density data is not well formed, and provides the column name from the attribute table, which is not useful to the map reader. Instead of the word counties, and POP07_SQMI, a more appropriate legend title would be ‘Persons per square mile’. Looking at the numbers to the right of each patch in the legend, it is not consistent with the number of decimal places. For instance, the bottom entry has no decimal places and is simply the entry 0 – 10, while the next three entries above it have two decimal places for the lower number and no decimal places for the higher number, while the top entry has two decimal places for the lower number, and one decimal place for the higher number. Since we’re talking about persons, we should round to the nearest whole person. The bottom two entries referring to Canada and Mexico background, and the ocean background, are not required for this legend, as the water and surrounding countries features aren’t unfamiliar for the map reader, and therefore, do not need to be placed on the legend. Additionally, the symbol for the ocean background on the legend blends in with the actual ocean background behind it, therefore, making it look like there is no legend entry for the ocean background.

Now let’s focus on the map itself. The United States is slightly off center and could be made quite a bit larger to fill the page. There is quite a bit of white space above and below the main feature the map, which is considered wasteful.

Additionally, only the Southern tail of Alaska is shown on the map, which looks sloppy, and makes the map reader wonder why only a portion of Alaska was shown. By enlarging the contiguous United States, the tail of Alaska would not be shown. If we consider the features included on the map, we have County outlines, roads, and rivers. The question becomes: “Are roads and rivers really necessary to show a map of population density?” Perhaps the roads, and/or rivers should be left off the map so that it is less cluttered and simpler to read. Additionally, the color of the roads is very close to the color of the most densely populated area, which makes it hard to see exactly what is going on in the counties underneath the roads, and smaller counties may be completely covered by road lines, therefore making it look like a County is densely populated when it is not.

Moving to the map projection, it’s clear that this map is not any particular projection based on the flatness of the northern boundary line of the United States. As the data that we are showing is based off of population per square mile, an equal area projection should be applied to this map as relative size is important when determining how dense counties are.

Another thing to note about the map, is that although Canada and Mexico are included, South America is not. If you’re going to include surrounding countries, you need to include all of the surrounding countries that my show up on the map.

Lastly, there is no neat line surrounding the map. In order to provide a nice frame for the map, and to have it stand out against its surroundings, a neat line should be included.

Here’s the same map with all the issues highlighted. As you can see, what may initially look like an ‘OK’ map, really has many, many problems.

This is a redesign of the map. This redesign took about five minutes of time, and made the map significantly more attractive, and useful. Note that the title is much more descriptive. It states that it is the population density for the year 2007, and specifically notes that it is for the contiguous United States of America which lets the map reader know that Alaska and Hawaii are purposely excluded for map. The projection is changed to an equal area projection that allows for the map reader to make proper areal comparisons between counties. The roads also been taken off the map which allows for the counties to be the main focus of the map and not be obscured. The scale bars have been greatly reduced in size, are using round numbers, in meaningful units. The North arrow has been greatly reduced in size and placed in a better location. The metadata is more descriptive and is a good size. The legend has been reduced in size has been given a descriptive title, and the numbers are now consistent with respect to the number of decimal places. Around the map is a nice frame.

Even with this redesign, one could argue there are still a few issues. For instance, the metadata is placed on top of some background data which makes it a little difficult to read. Additionally, the scale bars are half on and half off of Mexico, and rivers are still included on the map, which might be a feature that is not required. However, overall, with just a little extra work, and careful consideration, we’ve gone from a very poorly designed map, that was hard to read, and not pleasing to the eye, to a well-designed map that is much easier to read and is pleasing to the eye. Remember, map design is an iterative process. Don’t be afraid to radically redesign your map a few times to see how you might improve it. Also, show your map to a friend, family member, or colleague, and get feedback. Even though they may not be trained in cartography, people can often easily identify an ugly map, and might provides an important perspective on your map design.

4.6 - Example Map Critique.pptx