Skip to content

5-5. Use the JSON editor

So far in this tutorial we have configured categories in four ways:

  • Defined categories one by one in the Categories editor — for the COG layer in 5-3 and the WMS layer in 5-4.
  • Populated categories from a COG's sampled values and embedded colour map, then edited the labels — COG layers only (5-3).
  • Imported categories, colours and labels from a CSV file (5-3).
  • Copied the category definition from one layer to another.

A further, more advanced technique is to edit the layer's JSON directly. This is useful for bulk edits, or for pasting in a complete category set in one go.

Recall that we now have two World Cover WMS layers: World Cover 2021, added in 2-9, and World Cover 2020, added from the MapProxy service in 3-3. The 2021 layer already has its categories — we copied them across from the COG in 5-4. In this exercise we will use the World Cover 2020 layer to explore a direct JSON copy of a complete category set.

The Configuration Builder provides two JSON editors — one for the whole configuration (on the JSON config tab) and one scoped to a single layer (a small orange {JSON} icon on the layer card). This tutorial uses the per-layer editor.

Export first

Hand-editing JSON bypasses the safeguards built into the Categories editor, so export your configuration before you start. That way you always have a working copy to fall back on.

  1. Copy the following JSON to your clipboard:

    "categories": [
  { "color": "#006400", "label": "Tree cover", "value": 10 },
  { "color": "#ffbb22", "label": "Shrubland", "value": 20 },
  { "color": "#ffff4c", "label": "Grassland", "value": 30 },
  { "color": "#f096ff", "label": "Cropland", "value": 40 },
  { "color": "#ff0000", "label": "Built-up", "value": 50 },
  { "color": "#b4b4b4", "label": "Bare", "value": 60 },
  { "color": "#f0f0f0", "label": "Snow and ice", "value": 70 },
  { "color": "#0064c8", "label": "Permanent water bodies", "value": 80 },
  { "color": "#0096a0", "label": "Herbaceous wetland", "value": 90 },
  { "color": "#00cf75", "label": "Mangroves", "value": 95 },
  { "color": "#fae6a0", "label": "Moss and lichen", "value": 100 }
]

  2. On your World Cover 2020 layer card, click the {JSON} icon to open the JSON editor, then click Enable editing to switch from the read-only view to edit mode.

    JSON editor icon highlighted on the World Cover 2020 layer card

    The {JSON} icon on the layer card.

  3. Scroll down to the categories section. It reads "categories": [] — an empty list, because we have not given this layer any categories yet.

  4. Highlight the entire line of the empty categories ("categories": []), and then press paste to replace that one line with the clipboard copy from above. Apply changes and preview the layer — the legend now shows a row per class.

Full-config JSON editor

The full-config JSON editor lives on its own JSON config tab and is useful for larger edits. See JSON config.