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Eyes of a satellite: Iceland’s volcanic activity

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About the map

A hundred years ago, studying the earth’s surface involved actually being in that area of interest and conducting land surveys. In the last fifty years we’ve rocketed forward. Today, satellites not only capture what the world looks like in natural colour (how our eyes perceive light), but also allow us to visualise Earth in ways that would otherwise go undetected by our, comparatively simple photoreceptors.

This ArcGIS StoryMap shows the 2024 eruption on the Reykjanes peninsula, near Grindavík, Iceland from a satellite’s perspective. You can flip through the layers, each showing the imagery differently based on its combination of light waves. These combinations highlight specific features on earth’s surface, like heat or vegetation.

Why it works

The app has three layers for three different views that the Landsat satellite uses.

1) Natural colour – shows how our eyes perceive the world.

2) Colour infrared – while typically used for monitoring vegetation health, you can also use it to see the lava flow escaping the volcano. Both the lava, and the lush vegetation along the Icelandic coast, are a deep crimson.

3) Shortwave infrared – helpful for identifying fires and hotspots, even through clouds or smoke. The eruption is a burst of orange, with the surrounding vegetation in green and more reflective surfaces (like snow) in purple.

With its simple layout, we chose the Basic Instant App to bring the imagery to the foreground.

Important Steps

  • 1.

    Pick your imagery – the Image collection explorer lets you filter images within the layer to find individual images best suited for your needs. We filtered by the date and cloud cover.

  • 2.

    Experiment with templates – processing templates act like a filter over your imagery, applying a preset visualisation to show imagery in a different view. Templates will show different things, so understanding their purpose will help you select ones best suited for your dynamic imagery layers.

  • 3.

    Practice your workflow – take advantage of the great resources Esri and Esri UK have to offer, including this blog which inspired the basis of our map (thanks Bern)! 

  • 4.

    Add additional context – there is a wealth of information available to you in the ArcGIS Living Atlas of the World, which can provide other insights into your data. In this case, having thermal hotspot data helped confirm the volcanic activity. 

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Requirements

  • Data and software

    All the data used came from the ArcGIS Living Atlas, including Multispectral Landsat imagery and MODIS Thermal Hotspot data. The map was made in ArcGIS Online’s Map Viewer, and the web app is an ArcGIS Instant App template

  • Time

    We spent a few hours putting this project together; starting with following the workflow that Bern laid out and then configuring a web app. Another hour or two was spent testing its user friendliness and putting together the final touches.

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Tips and tricks

  • iceland's volcanic activity tip 1

    Exclusive layers

    Group layers have the option for Exclusive Visibility. This helps manage the map’s visual hierarchy and keep the viewer’s attention focused.

  • iceland's volcanic activity tip 2

    Read the metadata

    It is important to understand what your data is showing. For the MODIS layer, it notes that there can be ‘false positives’, as the data set will detect any large thermal signal (e.g oil wells).

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Links & Resources

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Eve Selbie

Map Author

Eve Selbie (she/they)

Eve works for the Product Communications team at Esri UK. When they aren’t making maps, their time is spent convincing themselves that Scottish water isn’t too cold to swim in.

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