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Are Deprived Areas of Great Britain more at Risk from Sea Level Rise?

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About the map

Climate change is becoming ever more present and brings with it the threat of sea level rise. With some areas of the world beginning to feel the effect today, we wanted to investigate the relationship between an extreme coastal inundation scenario for Britain and the impact that this would have on vulnerable populations. The human impact of climate change is often cited but mapped less.

Why it works

The interactive app lets you explore the risk to Great Britain. Using the swipe tool within the Media Map ArcGIS Instant App, you can instantly observe the relationship between deprivation and Sea Level Rise (SLR). The map is interactive, letting the user see if a location important to them may be at risk.

Important Steps

  • 1.

    A copy of the OS Terrain 50 data was downloaded. Python was used to automate the process of extracting the Digital Elevation Model (DEM) files and collating them into a file geodatabase.

  • 2.

    Using the ArcGIS Pro Raster Calculator Geoprocessing tool, all areas below the elevation threshold were revealed. Using the Classify tool this was classified as its own layer.

    Next, using the Raster to Polygon tool, the layer was converted into a polygon so it could be better represented on a map. This also allowed for the layer to be clipped to the British coastline. 

  • 3.

    The map created in ArcGIS Pro was published to ArcGIS Online as a web map. Here the deprivation layers were added, and the cartography was finalised using blending. Pop-ups were also turned off to reduce complexity. 

  • 4.

    The Media Map Instant App was chosen, as it provides an easy-to-use interactive app with basic tools and navigation. The Swipe tool was set up to allow users to interact with the map layers. Finally, the info panel provides a space to document what the map shows as a user is welcomed to the app. 

     

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Requirements

  • Data and software

    DEM data for flood modelling was sourced from OS Terrain 50. Using the raster calculator and other geoprocessing tools in ArcGIS Pro, we set an elevation level to model flooding under 4.6m. ArcGIS Online was used to configure a web map in Map Viewer and to customise the data visualisation. ArcGIS Instant Apps brings intuitive mapping experiences to an audience that might not be familiar with GIS. Within five minutes we had selected a template and tailored the web app to our audience's needs.

  • Analysis

    We modelled coastal flooding using the raster calculator tool in ArcGIS Pro, identifying land that was below or equal to 4.6m in elevation. Then, raster data was reclassified into only one class which was below the 4.6m threshold. This was then converted to a polygon and clipped to the coastline, with only areas hydraulically connected to the coast being shown. Polygons that were too small were removed to cut back on anomalies.

  • Time

    It took a couple of days to unpack OS data and collate the data using Python. Working out the best workflow for modelling coastal inundation using a DEM and creating coastal inundation polygons for each OS National Grid Square took another couple of days. Uploading the data to ArcGIS Online and setting up symbology in Map Viewer took a couple of hours. Creating and finalising the Instant App was also completed in a couple of hours.

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Tips and tricks

  • tip-1-sea-level

    Don’t be afraid to use Python

    Simple scripts make data processing tasks more efficient.

  • tip-2-sea-level

    Use meaningful layer names

    When you create or add new layers, using descriptive names will help you avoid getting confused or lost in the data!

  • tip-3-sea-level

    Engaging apps

    ArcGIS Instant apps is a great web app option to make data interactive and accessible.

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Links & Resources

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Joshua Savory

Map Author

Joshua Savory (he/him)

I am a Graduate Consultant at Esri UK, with a background in Physical Geography at University. I enjoy getting outdoors especially on a bike! I am passionate about using GIS for renewable solutions.

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