Skip to content

5-3. Categories for a COG

The category system determines how COGs are rendered when their values represent a data classification (as opposed to a continuous variable).

  1. Create a new layer card called World Cover - Austria in the Land Cover interface group - see tutorial 2-6 for a recap if needed

  2. Add the following dataset — a World Cover COG for Austria - see tutorial 2-7 for a recap if needed:

    https://esa-apex.s3.eu-west-1.amazonaws.com/APEX-example-data/constraints/PowerDensity_100m_Austria_WGS84_COG_clipped_3857_fix-esa_worldcover_2021.tif

  3. Click the (i) info icon on the dataset row to open the COG metadata dialog.

    COG metadata dialog showing categorical statistics and the embedded colour palette

  4. Use one of the category buttons to populate the editor:

    • Populate categories (or Copy unique values to config categories) adds the classes found in the COG sample to the config, assigning arbitrary colours automatically. This is the fallback when a COG does not have an embedded colour map.
    • Copy embedded colormap to config categories copies both the class values and their original colours from the COG itself. Use this option when the COG has an embedded colour map — this is the case for the World Cover Austria COG, so it is the preferred option here.

  5. Edit a couple of the category labels to align to the World Cover class names (e.g. 10 → Tree cover, 30 → Grassland). See the WorldCover class lookup below for the full list of values, colours and names.

    Edit Categories dialog for the World Cover COG layer showing populated categories with labels and values

    To save on manual typing you can also import or export categories from CSV files. If you want to do this quickly, download world-cover-classes.csv and then import it from there.

  6. Save the layer card and preview. The COG is now rendered with the labels and colours you defined.

    The values are populated from a sample of pixels. It is possible for a small number of pixels to fall into classes that were not sampled. Cross-check against the source data if completeness matters.

  7. (Optional) Go back to Data Visualisation → Categories → Edit and change the colour of one class — for example, make Tree cover a light green. Save the layer card and preview again. The configured colour overrides the colour map embedded in the COG, so the legend and map rendering reflect your choice rather than the built-in palette.

WorldCover class lookup

Value Colour Colour code Class name
10 #006400 Tree cover
20 #ffbb22 Shrubland
30 #ffff4c Grassland
40 #f096ff Cropland
50 #fa0000 Built up
60 #b4b4b4 Bare / sparse vegetation
70 #f0f0f0 Snow and ice
80 #0032c8 Permanent water bodies
90 #0096a0 Herbaceous wetland
95 #00cf75 Mangroves
100 #fae6a0 Moss and lichen
0 No data

Source: ESA WorldCover collection documentation