Monday, February 3, 2014

Oh, hello Asiafrica!

How to use Wikipedia to create animated maps.

Geodata is everywhere but there is one major obstacle that prevents constructing beautiful maps with it. Many databases are containing all elements to provide geodata but lots of these databases are not intended to supply users with geographic information and attributes in a way that you can easily use them for mapping. There are thousands of ideas for possibly amazing maps that could be created if there was sufficient data or time to extract and prepare it. 

If you want to produce geodata by yourself, a look at Wikipedia can be very helpful. There are lists of earthquakes, most western points of countries and so on that contain lat and lon values already. You can easily import these using the Add Delimited Text Layer function in QGIS. Moreover there are lists that contain geographical information that you can symbolize by a country’s or city’s name. The utilization of these lists for GIS is sometimes a little bit tricky. For example, the list of terrorist attacks would need some geocoding whereas data that is linked to a whole country can be visualized using the Join function.

The recent project about where the bad guys vote made me interested in creating another cartogram. Inspired by the demographic animation of Germany I decided to also work on a project that shows a development within a certain period. 

The Wikipedia list of countries by past and the future population provides the population of nearly every country from 1950 to 2050 in a 5 years interval. Thus, it is possible to generate 21 cartograms to visualize the whole Wikipedia list in one animation.

To import the list we can take the link of the demanded Wikipedia site, open Excel and paste it into the File Name text box just like we would open any other file stored on our computer. The whole site will be opened and look a little bit clumsy but it is now easy to extract the list data in a new worksheet and we can prepare the data to join it with a global dataset that includes country names. I decided to take data from Natural Earth.

After saving the joined data to a new Shapefile, we can start creating cartograms with Scape Toad for every year. It will take some time!
By the creation of 21 cartograms, we have a good number for our animation. After styling and exporting each cartogram via QGIS’ Print Composer the cartograms can be compiled to an animated GIF by using an image manipulation programme like GIMP

Lots of Layers and a lot of handwork for styling and export

Creating an animated GIF with GIMP

It took me some time to figure out a decent styling. In fact, I do not like this colourful presentation of the continents but it turned out to me the most reasonable styling. First, I tried to use one graduated colour for all continents but it made the impression that there is some kind of order or importance within the continents. Thus, I ended up using the colourful symbolization.

As you can see, the animation illustrates the decrease of population in Europe compared to Asia and then at around 2015 also in relation to Africa. It seems to be only a matter of time until the Europeans actually need something that is more forceful than Frontex to “protect” against refugees crossing the Mediterranean Sea.


Felipe said...

Great! Where did you get the earths shapefile? openstreetmap? Maybe you can use some data from the worldbank or UN, FAO and so on. Or is it easier to import data from wikipedia (in most cases wikipedia uses date from the institutions mentioned above).

Gideon said...

The earth Shapefile is from Natural Earth. They offer a lot of consistent global datasets that can be used freely.

I chose to import data from Wikipedia to show that you can sometimes help yourself, if there is no prepared Shapefile. Moreover, Wikipedia offers in some cases the combination of several data sources.
Actually, I requested to use some UN data, because their data has a lot of restrictions when you want to publish it (even non-commercial). I am still waiting for a response. Always take care on copyright restricitions. They might cost you a lot of money.

Anonymous said...

Hola amigos, También uso natural de la tierra, como ya se ha dicho, es no tener derechos de autor. Esta vez, la tarjeta es super bueno. 
El video es muy informativo. los problemas de la población mundial son particularmente evidentes en África y Asia.