Categorical visualizations

Categorical visualizations use a categorical attribute and the categories within it to apply styling to discrete categories of the attribute. On raster datasets, it uses a band instead of an attribute.

Categorical visualizations are defined using "type": "categorical" and, for every supported style and label property used, either a single value that will apply to all categories or an array of different values for each category.

Vector example

The Global Power Plants layer in Felt is an example of a categorical layer on a vector dataset

and is defined by the following style

{
  "version": "2.3",
  "type": "categorical",
  "config": {
    "categoricalAttribute": "primary_fuel",
    "categories": ["Solar", "Hydro", "Wind", "Gas", "Coal", "Oil", "Nuclear"],
    "showOther": false
  },
  "legend": {"displayName": {}},
  "attributes": {
    "capacity_mw": {"displayName": "Capacity (MW)"},
    "name": {"displayName": "Name"},
    "primary_fuel": {"displayName": "Primary Fuel"}
  },
  "paint": {
    "color": [
      "#E5C550",
      "#7AB6C2",
      "#AB71A4",
      "#CC615C",
      "#AD7B68",
      "#EB9360",
      "#DEA145"
    ],
    "isSandwiched": false,
    "opacity": 1,
    "size": [{"linear": [[3, 1.5], [20, 8]]}]
  }
}

Notice that we are saying that the primary_fuel data attribute will be used to categorize elements and that the possible values of that attribute that we are interested in are "Nuclear", "Oil", "Coal", "Gas", "Wind", "Hydro" and "Solar". Also notice that we are defining either a single value that will apply to all categories (i.e. size) or a value for each category (i.e. color)

Raster example

The Cropscape CDL layer in Felt is an example of a categorical layer on a raster dataset

Screenshot 2024-04-12 at 13.25.09.png

and is defined by the following style:

{
  "version": "2.3",
  "type": "categorical",
  "config": {
    "categories": [
      254,
      250,
      249,
      248,
      247,
      ...
      4,
      3,
      2,
      1,
      0
    ],
    "showOther": false
  },
  "legend": {
    "displayName": {
      "0": "Background",
      "1": "Corn",
      "2": "Cotton",
      "3": "Rice",
      "4": "Sorghum",
      ...
      "247": "Turnips",
      "248": "Eggplants",
      "249": "Gourds",
      "250": "Cranberries",
      "254": "Dbl Crop Barley/Soybeans"
    }
  },
  "paint": {
    "color": [
      "rgb(38, 113, 0)",
      "rgb(252, 105, 101)",
      "rgb(252, 105, 101)",
      "rgb(252, 105, 101)",
      "rgb(252, 105, 101)",
      ...
      "RGB(255, 158, 15)",
      "RGB(0, 169, 230)",
      "RGB(255, 38, 38)",
      "RGB(255, 212, 0)",
      "rgba(0, 0, 0, 0)"
    ],
    "isSandwiched": false,
    "opacity": 0.93
  }
}