Animating Extinct Volcanoes

Here’s an illustration of the evolution of Banks Peninsula, near Christchurch. 15 million years in 15 seconds.

The images come from Extinct Volcanoes, a booklet on the geology of Banks Peninsula. As soon as I saw the time series of drawings I thought, “animated GIF!”

These are my notes on how I did it.

The book was published by the Geological Society of New Zealand in 1985. You can download it as a PDF from ResearchGate: Extinct Volcanoes: a guide to the geology of Banks Peninsula. The images I used come from Fig.9 on pages 14 and 15.

I did the drawing in Inkscape, exported a set of SVG images, and animated them in PowerPoint.

As a base layer I grabbed a map of Christchurch and Banks Peninsula from OpenStreetMap. (© OpenStreetMap contributors)

In Inkscape I added the map and created a layer to trace the coastline. I’m an Inkscape novice but found useful tutorials on YouTube. TJFree’s short tutorial on how to trace images with the Bezier tool gave me what I needed.

The outline of the coast is the guide line in every frame of the animation. The coast didn’t exist when the volcanoes were forming but it helps frame the illustrations.

There are eight stages of evolution shown on the original figure. I created an Inkscape layer for each and copied and pasted the original images from the PDF. Each layer from the book needed to be aligned and scaled to the coast outline. Then I added a new tracing layer for each image and traced over the originals, red for active volcanism and grey for the older, eroding rocks.

I saved each frame independently, removing all of the layers I didn’t want, giving me a series of images.

Creating the GIF turned out to be dead easy. PowerPoint 365 has a built-in function for exporting a slide show as an animated GIF, including timings and animations.

I’ve had Inkscape installed for years and it’s good to finally use it. PowerPoint is one of my favourite tools but there are plenty of capabilities to discover.

The end result is simple but effective and helps illustrate the origins of the landscape we live in.

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