As described earlier in the section on cartography, Map Design is among the final stages of producing a map. But at the same time, it makes for most of the impact of the overall process.
What is map design? Choosing eye-pleasing colors and textures? Yes, that, and much more. While map design is perhaps simpler than rest of the process involved in mapmaking, it is nonetheless challenging in itself.
And this detail comes from a GIS system, which has been explained elsewhere. We will now look at the prerequisites of Map Design, and how the process is carried out in practice.
In order to produce a good map design, there are certain imperative concepts with which one needs to be familiar. Let's look at the quickly.
2.1 Types of maps
This has already been explained, but for the sake of completeness, here's the essence. Broadly, there are two types of maps: reference, and thematic. Reference maps are those that give information about a place, or show the details in some way. For example, a road map, a political map, etc., are examples of reference maps. On the other hand, thematic maps are used to show the pattern or distribution of something on a map. For instance, world GDP map, climate map, literacy map, etc., are all thematic maps. Of course there is no limit to the type of thematic maps you can create. You can have maps on number of neighbor fights around the world, if you so wish!
You already know what a map scale is. But its implications are important for the map designer. Consider the simple fact that there is only limited area to print the map, and so one is confronted with the choice of scale. You can include more of a map if you keep the scale large, but then you lose much detail. Which of the information on the map is most useful? Which parts of the map are the most useful? How large is the finished map going to be? Will it be able to focus properly on its goal?
These are some of the important questions a map designer has to ask himself when selecting a scale for the map.
This may sound something trivial, but the scale is actually the most important factor. Choosing a wrong scale will ruin the whole map, no matter how good the printing quality and other processes happen to be.
2.2.1 Understanding Map Scale
Some people have trouble understanding map scale. They think that a map that is drawn on a small scale should naturally have more detail. But if they compare two maps with different scales, it leads to confusion.
The thing to be understood here is the nature of the scaling factor. Scale is nothing more than the zoom-in factor. A smaller scale would mean that we are not zoomed-in that much, and hence we can represent a larger portion of the land on the same area. A larger scale, however, means that we are zoomed in a lot more, which means that only a smaller portion of the land would get drawn on the map. On the plus side, this allows us to plot much more detail in the given area.
Finally, the scale should not be directly understood from the numerical value given in the map. A scale factor of, let's say, 1:300,000 is small scale, and not large scale. This is where the confusion comes in, and should be avoided at all costs.
2.2.3 Selecting a Map Scale
While the map designer is generally free to pick any scale he chooses, the scale of the map must correspond to that of the data available. Yes, the GIS system again comes into play here. Data generated in a GIS system is for a particular map scale, and works best for that case only.
This is not to say that you can't create the map on a different scale. You can, but there will be side-effects: 1) You will lose a good amount of detail on the map; and 2) The map will look weird. The latter part is a natural consequence of not having enough data to plot the terrain.
2.3 Map Projections
Map projections have been explained in a separate section. A map designer must be aware of the final utility of the map, and needs to select a relevant projection. While the Miller projection is the most famous one, we already know that it introduces severe distortion near the poles. Which means that a map designer must be aware of these issues and choose wisely.
3. Map Generalization
When all these things have been figured out, it is time for map generalization. Map generalization is a broad term, and includes many smaller processes. Let us have a look at them one by one. Do bear in mind that the final aim of map generalization is simplification of data and representation, so that a useful map could be created.
4. Selection and Simplification
These twin-processes are used to make the available data set simpler to use. Why would we want to make a data set simpler? And anyway, what does it mean to make the data set simpler?
In a GIS system, there is a great level of detail. The average amount of data stored in a professional map would become impossible to handle if a single person were to try doing that manually. This calls for some modification of the data at hand. Since most of the maps we use in everyday life are not going to be used for surveying purposes, they do not require too much detail. In fact, cramming too much of information into a map can only serve to dissolve its meaning and usefulness.
Achieving such a simplification is not easy. It involves far more than doing a basic filtering, especially because the actual data sets are far complicated.
The process of classification is a natural consequence of the need to handle detail. Again, consider an example to help in understanding the concept. Suppose you are developing a thematic map on the net exports of the world countries. Now suppose you have data on 150 of the countries; how are you going to represent this on the map? Creating 150 shades of a single color, or even 150 different colors is going to defeat the primary purpose: usefulness. When such level of detail is present in a map, it is actually no different from the data set it was constructed from, and so loses its value.
Well, well, we seem to be in a fix! What is the way out? The simple process of classification. We start with grouping together data values that are close to each other, by defining a minimum-maximum range for them. This range is also known as a class, hence the name. Ideally, you can aim for anywhere from 4 to 6 classes, as this is the acceptable number of single-color gradations in a map.
Keep in mind that classification is also quite complicated, given that the data values generated by the GIS system may contain many irregularities.
6. Symbolization Ideally
A map usually has to carry more than one type of information, and if we go on using nothing but colors, it will soon start to look a patchwork. Therefore, certain pieces of information are to be represented by some other means, such as, symbols. You might recall from watching fantasy movies that forests are represented on maps by closely huddled trees. Although that convention would be laughed at today, it gives a good idea about symbols.
Not all symbols need be straightforward to decipher. Most of the maps provide the meaning of the symbols in a small section known as the legend. Since there are usually not more than 4-5 different symbols to be differentiated at a given time, this poses no problems.
A final note of warning before we leave the rather apparently flimsy concept of symbolization: symbols should be chosen wisely, keeping in mind the profile of the end-user, as well as the overall color-theme of the map. At the end of the day, the map designer's job is to make the map useful to the people who are going to use it.
7. Map Composition
When all the previous items have been figured out and the processes defined, it is time for the map designer to enter the final stages and apply himself. Perhaps you are already overwhelmed and asking, "Well, haven't we been doing map composition only all along?!" Well, yes and no. Yes, because certainly map composition does not have a definition cast in stone. No, because that is not what map composition is commonly meant to be in the practice of cartography.
Map composition is closer to the visual design process than any of the foregoing. It is here that the map designer has clarified all the inputs from the previous stages, and having done so, must close his eyes and visualize the final map. This would mean thinking about the various color-themes and font sizes, as well as how the scale is going to be represented. He would strive to achieve the best contrast, and perhaps visual effects like 3D surface.
Also, this stage calls for being very particular about line-spacing, placement of titles, choosing a font-face, etc. Any slight laxity here can spoil the whole map, and so enough caution can never be exercised.
Fuse all these processes together and the map is ready: comprehensive, compact, and beautiful! But be aware that the process of map design was presented in its simplest form here. The idea involved in professional cartography are complex enough for one to start feeling dizzy after the study of a page or two, but we have tried to keep the score straight and help you grasp the basics right.
What next? Why, purchase a book on map design, invest in a good GIS system, and get ready for the harder but more satisfying part of this journey. But if you are like most people, you are happy getting to know the process is more than superficial detail, and leaving the experts to themselves.
Whatever you decide to do, the joys of cartography are many and to be enjoyed by all.