The visualization of the data is a very helpful process to have perspective of the current situation in which we find ourselves. It is useless to have many figures in front of us if we do not know how to draw valuable conclusions from them.
If we focus on the field of geolocation, thematic maps are the most useful tool to check at a glance the status of some processes and their evolution over time.
According to the characteristics of those factors that we want to study, it will be more convenient to carry out one type of representation or another. Through the following lines, we will go on to describe which are the types of maps currently used for the representation of information.
Steps to develop a thematic maps
Plasmating reality using visual representations in the form of maps is a complex process that requires a precise and exhaustive methodology. Through a series of predefined stages, it is possible to represent reality in a direct and attractive way.
The first question to answer when designing a map is “What do I really want to represent with this map?” Once we have defined the purpose and the variables necessary to reach it, we will have to delimit geographically the area to which we want to represent and in which the phenomenon object of study is manifested.
Another important variable to take into account would be if the object to study will remain fixed on the map or will be moving through it. For example, in the case of maps on people flows or traffic movements.
The next step will be to collect the necessary data for the representation. These will depend on the number of variables to be analyzed, thus being able to classify the maps as univariate, bivariate or multivariate.
Traditionally, the data captured in thematic maps were consulted through analogical repositories such as censuses or results of statistical studies or surveys conducted for that purpose.
Currently, this process has changed markedly. The sources of information have multiplied, in addition, many data have acquired the value of being collected and processed in real time, bringing us closer to a representation more true to reality.
Nowadays, mobile devices and localized sensors, both outdoors and indoors, are continuous generators of information that is dumped in public or private databases.
Once we have all the necessary information for our thematic map, we will have to solve some aspects about how to represent them graphically. In this stage, we must define the degree of detail of the thematic map, the projection system, what elements we want to appear, the scale, the symbols, colors, text fonts and other necessary factors from the design point of view.
Types of thematic maps
Once all the previous considerations have been assessed, the thematic map itself will be elaborated. We can classify these maps according to the different techniques of elaboration of these. Next, we are going to talk about the most outstanding ones.
In these maps, predefined regions are colored or shaded. The intensity of the same color or of a shadow is related to different quantitative graduations, while different colors represent different qualitative variables.
A habitual case of the use of choropleth maps takes place in the scope of the climatic and meteorological study. For example, we can appreciate it in the solution that Geographica developed for the Climate Research Group, climate research group of the University of Seville.
Specifically, we carried out a Geovisor called Global Climate Monitor through which the historical evolution of variables such as precipitation or temperature could be analyzed thanks to the information obtained through Open Data collected from some 4,000 meteorological stations scattered throughout the planet.
This kind of cartographic representation shows the intensity of a certain aspect depending on a color gradation. Up to this point, there is no difference with the choropleth maps, which is that it does not apply to predetermined areas, but that specific points are measured.
The use of heat maps is very widespread, applying in a wide range of fields and sectors. To mention one of its most popular applications, in recent times its use has been generalized to represent statistics of sporting events. In the digital world, it is usually very common to apply heat maps to study which areas of a web page are the most visited by visitors and improve their design.
At Geographica, we have implemented heat maps in some of our solutions. We can bring to the forefront Urbo, a project developed together with Telefónica for the creation of dashboards applied to the management of Smart Cities.
In Urbo, heat maps are used, among other cases, to monitor the efficiency of the garbage collection system in different areas of a locality.
Proportional symbol maps
In these maps, a certain symbol is associated with a variable of a region. Some graphic property of said symbol, such as its area or volume, expresses in scale the dimension of this variable.
Although the catalog of symbols that can be represented is very broad, the variation in the size of these can be better appreciated by using squares and bars. However, the symbol most used historically has been the circle.
A simple example of a map of proportional symbols would be one in which the population of different cities is visualized by circles of different sizes.
Point distribution maps
To give shape to these representations, each point corresponds to a specific incidence or to a pre-established number of them.
These point distribution maps are widely used to record the incidence of diseases.
Obviously, in this type of maps the accuracy is fundamental when placing the point in the geographical place where the phenomenon to be collected took place.
We can see distribution maps of points in the Geomarketing solution that we developed in order to locate the best locations to open new establishments in Barcelona for a specific client. This was based on locating, thanks to different sources, where the people belonging to the segment of the population that constituted their target audience lived.
Cartograms are a type of visual representation of data that are very striking to the viewer. This is because geographical areas are distorted depending on the value of the variable to be represented. We could say that it is similar to proportional symbol maps, with the peculiarity that the symbol is the map region itself.
The main drawback of the cartograms is that if the observer does not know the real dimensions of the geographical area represented, he is not able to appreciate the degree of distortion of it.
As we can see, there is an interesting variety of visual representations of data from the geographical point of view. The large amount of information that we can access makes the creation of maps a transcendental step to achieve optimal management of processes.
We are used to seeing maps from children, but we have rarely stopped to think about why some characteristics are represented in a way and others in a completely different way. We hope that with this article, in which we have dealt with the most commonly used maps, we have managed to clear up some doubts about it.