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Highlight a set of regions

Sometimes you don't have numbers. You have a list — covered markets, member states, portfolio countries, affected territories. The regions= parameter handles exactly this: named regions receive the theme's highlight color; everything else stays in the neutral land fill. No legend is generated because there is no scale to explain.

What you'll build​

A world map showing EU member states highlighted in a single accent color, everything else in the theme's default land color.

EU member states highlighted on a light-blue world map

Steps​

  1. Choose the regions you want to highlight. Collect the ISO 3166-1 alpha-2 codes for each country (or ISO 3166-2 codes for subnational scopes). Separate them with commas — no values, no colons.

    regions=DE,FR,IT,ES,PL,RO,NL,BE,SE,AT,CZ,PT,HU,SK,DK,FI,IE,HR,BG,LT,LV,SI,EE,CY,LU,MT

  2. Pick a theme. The highlight color is theme-specific: a muted blue for light-blue, amber for dark, grey for light-mono. No other theme parameters are needed.

    theme=light-blue

  3. Assemble the final URL and embed it.

    https://api.maproll.io/map.svg?scope=world&regions=DE,FR,IT,ES,PL,RO,NL,BE,SE,AT,CZ,PT,HU,SK,DK,FI,IE,HR,BG,LT,LV,SI,EE,CY,LU,MT&theme=light-blue
    <img
      src="https://api.maproll.io/map.svg?scope=world&regions=DE,FR,IT,ES,PL,RO,NL,BE,SE,AT,CZ,PT,HU,SK,DK,FI,IE,HR,BG,LT,LV,SI,EE,CY,LU,MT&theme=light-blue"
      alt="EU member states"
      width="800"
    />
    EU member states highlighted

Variations​

  • Change the theme to shift the highlight color. dark gives an amber accent on navy; light-mono gives a grey highlight suitable for print:

    https://api.maproll.io/map.svg?scope=world&regions=DE,FR,IT&theme=dark

  • Subnational scope. Swap scope=world for scope=RO and use ISO 3166-2 region codes to highlight specific counties:

    https://api.maproll.io/map.svg?scope=RO&regions=RO-B,RO-CJ,RO-TM&theme=light

  • Add a title to explain what the highlighted regions represent:

    https://api.maproll.io/map.svg?scope=world&regions=DE,FR,IT&theme=light-blue&title=Coverage+markets&subtitle=Q2+2025

  • Combine with annotations to add hover tooltips explaining why each region is highlighted, without numeric values:

    https://api.maproll.io/map.svg?scope=world&regions=US,CN,DE&annotations=US:Primary+market,CN:Growth+target,DE:Distribution+hub&theme=light

    See Annotations for the full syntax.

  • Highlight in a POST body when your list is dynamic or comes from an API:

    curl -X POST https://api.maproll.io/render/map \
      -H 'content-type: application/json' \
      -d '{
        "scope": "world",
        "regions": [
          { "id": "US" },
          { "id": "CA" },
          { "id": "MX" }
        ],
        "theme": "dark"
      }'

    Regions without a value field are treated as highlight-only entries.

  • Themes — how highlight colors vary per theme
  • Scopes — available scopes and their region ID formats
  • Color overrides — assign a specific hex color per region instead of the theme highlight
  • Annotations — add hover tooltip text to highlighted regions