Cartography of Ireland since the 16th century: a map morphing experiment

Interest in cartography is a common thing online nowadays, so there is one thing I was surprised not to find easily: map morphing animations. For example, to show the evolution of maps along history. This sounds obvious once you think about it, but apparently this hasn't been done so often. This great North America animation is the only example I've found. So I did it myself.

Here is my first try, with Ireland.

I chose Ireland for a lot of reasons. Being an island, it is a limited territory where only natural borders need to be considered. Being relatively small, it's not subject to big distorsions due to different projections. It has some very distinctive geographic features, like a complex coastline and many great lakes. That would make matching easier between different maps, and differences appear more clearly. The history of Ireland cartography is also really interesting, with very different early maps, and a dramatic turn by the end of the 17th century. Last but not least, I love this country and know it well firsthand (I've just returned from ten days there driving round the island for the second time).

Disclaimer: Please bear in mind that this is just a cartographic and visual experiment, so it lacks the rigor of an historian work. Some dates may be wrong, and as I had to use some lo-res images with barely readable place names, a lot of matches in early maps are probably off. Please excuse any error you may find, and feel free to report them. I would love to have the time and resources to do it more rigorously.

Here are the sources I used:

Some nice things to note

You can clearly see them on the next two maps, and they appear more and more evanescent on the next ones, before disappearing completely.

These islands don't exist nowadays. At first I thought this was an example of bogus information transmitted from map to map. But I did some research and found old mentions of large sandbanks on the east coast from Dublin to Wexford (here in a French book). This must be it, exaggerated on early maps probably because it was a well-known threat for navigators.

Earlier maps

Of course there are maps of Ireland before 1566. Like this one:

From a 1528 atlas.
From a 1528 atlas.

… or this one:

Ptolemy map, 140 AD.
A ~1480 reconstitution of the earliest recorded map of Ireland,
appearing in Ptolemy Geography, in 140 AD.

… and many atlases and ancient navigation maps, where Ireland appears as a rough shape. But these maps are so far from the real thing that it's hard to work with them. I tried a bit, but I didn't know where to put the matching points and the morph rendering was terrible. So I started from the first map I found where some disctintive features begin to be clearly recognizable. Maybe it's worth a try with another morphing software?

Technical note

As a believer of free and open source software, I use free tools in all that I do. And because I'm stubborn, I continue to do so even when it borders on masochism :)

To achieve the morphing animation, I used Gimp and GAP, a quite outdated plugin for Gimp which adds animation capabilities. It includes a morphing tool which works by defining matching points between two images. Then it outputs morphing steps as a specified number of layers.

Screenshot of the Gimp morphing tool.
Screenshot of the Gimp GAP morphing tool.

To achieve a smooth transition, you need to define a lot of points, which I did between each pair of maps. I won't lie, it was tedious. Mainly because GAP is unstable and has a lot of UI gotchas. But after 3 or 4 maps done, I was really productive :).

I then used a ffmpeg command line to get a video from all the image frames. The editing work (adding captions to the video) was done with Kdenlive, which is quite good, especially compared to the other video applications on Linux. Et voilà !

Morphing in general seems rather old-school now, looking like something from the 90's, so there isn't a lot of available software. But I'm pretty sure there are easier alternatives to the process. So if you know of some tools that could help, even non-Linux non-free, feel free to comment.

Anyway, I hope you enjoyed it :)

  1. There is a great article about the history of the north-on-top convention on America Al Jazeera.