How to use a line layer as a background map

There may be situations where your map only contains some regions, and it can be difficult for a user to identify where these regions are located. In this case, you can use our line layer in the Projection map template to add an outline of a wider region as a background map. This is also a great choice to create a light-weight map that loads quickly across different devices.

In the example below, our Regions layer contains English counties colored in blue. Here, we've added a line layer with the outline of the UK that helps the user contextualize what part of the world they are looking at.

    1
    Begin with one of our Projection map starting points, or upload your regions to the blank map, and set a Value binding to color your regions.

    TIP: When uploading your own GeoJSON, we recommend file sizes up to 5 MB. Anything larger than that will reduce performance. To learn how to resize your GeoJSON file, head over to this help doc.

    2
    Go to the Lines tab and upload the wider region that you want to use as a background map. You can upload GeoJSON containing polylines, polyons and multipolygons to the line tab. In this case, we used a GeoJSON of the whole of the UK.

    TIP: If you don't have a GeoJSON at hand, you can copy the geometry from any of our map starting points.


    3
    Add the Geometry binding to your lines sheet and your outline will appear on the map.

    4

    If your Lines layer sits outside the bounds of your regions, you may need to toggle the Include lines data option under Projection in the settings panel.

    5
    Now go to the Lines layer settings, where you can change the style of your background map line. Here, you can customize the color, width, opacity, and dash-style. 
    Read more about the lines layer in our help doc.

Get started with your own Projection map now! »