Legends

Adding a legend block to a visualization makes a legend entry appear for this visualization.

Each legend entry is shown with the geometry type and color defined by the dataset and the visualization block.

While simple visualizations will generate a single legend entry, categorical visualizations will generate a legend entry per category.

To see how a legend is defined, take a look at the legend block section.

Simple legend

The Biodiversity Hotspots layer in Felt has a simple visualization with a legend defined as follows:

"legend": {}

Categorical legend

The Plant Hardiness Zones layer in Felt has a categorical visualization with a legend defined as follows:

"legend": {
  "displayName": {
    "13": "13: 60 to 70 °F",
    "12": "12: 50 to 60 °F",
    "11": "11: 40 to 50 °F",
    "10": "10: 30 to 40 °F",
    "9": "9: 20 to 30 °F",
    "8": "8: 10 to 20 °F",
    "7": "7: 0 to 10 °F",
    "6": "6: -10 to 0 °F",
    "5": "5: -20 to -10 °F",
    "4": "4: -30 to -20 °F",
    "3": "3: -40 to -30 °F",
    "2": "2: -50 to -40 °F",
    "1": "1: -60 to -50 °F"
  }
}

Numeric legends

The visual display of numeric legends varies based on the style method (stepped or continuous) and the geometry type (point, line, polygon).

The displayName can be modified in the legend block similar to simple and categorical style types.

Stepped

"legend": {
  "displayName": {
    "0": "5.14 to 19.46",
    "1": "19.46 to 26.43",
    "2": "26.43 to 34.06",
    "3": "34.06 to 45.06",
    "4": "45.06 to 100"
  }
}

Continuous

"legend": {
  "displayName": {
    "0": "2.34M", 
    "1": "714.65K", 
    "2": "33K"
  }
}

Heatmap legends

Heatmap legends are defined as follows:

"legend": {
  "displayName": {
    "0": "Low", 
    "1": "High"
 }
}

Notice that the displayName mapping goes from 0 (left value) to 1 (right value)