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8-4. Add the first statistics source

Statistics sources are added from their own tab, not alongside the display data.

  1. On the World Cover 2021 with statistics layer card, open Data Sources and select the Statistics tab.

    Statistics tab in the Data Sources section of the layer card

  2. Click Add source and choose the format FlatGeoBuf.

    Supported formats

    Statistics sources must be FlatGeoBuf or GeoJSON. FlatGeoBuf is preferred: it is indexed, so the Explorer only downloads the features in view.

  3. Paste in the NUTS level 0 (country) file:

    https://esa-apex.s3.eu-west-1.amazonaws.com/APEX-example-data/HI-RES-NUTS/stats.esa_worldcover_2021.nuts_2024.epsg4326.level00.fgb

  4. Note the level field. This is the first statistics source on the layer, so it is pre-filled with 0 — the coarsest boundaries. Leave it as it is.

  5. The zIndex is set to 100, above the display data, so that the clickable boundaries sit on top of the raster. Leave it as it is.

  6. Save the source. It now appears under Statistics, separately from the WMS source on the Data tab.

  7. View the result. Open the Preview, turn the layer on, then:

    • Select the Statistics tab in the info panel.
    • Click on a country on the map.

    You should see the land cover breakdown for that whole country:

    Statistics tab showing the World Cover class breakdown for Italy at NUTS level 0

Coordinate reference system

These files are published in EPSG:4326, matching the epsg4326 in the file name. Statistics features must be in a CRS the Explorer can reproject to the map — a mismatch shows as boundaries in the wrong place, or no clickable features at all.

Did you remember to export?