Generate data-driven visualization of unique values

This sample demonstrates how to generate a data-driven visualization with unique values based on an attribute field containing categorical (or nominal) data.

This is accomplished with the createRenderer() in the type renderer creator helper object. All that is required for generating a renderer is a Feature Layer and a field name.

The createRenderer() method returns a set of symbols best suited to the given basemap. Notice that as you change the basemap using the BasemapGallery widget, the fill and outline of the symbols slightly change to a lighter or darker theme to be more visually appealing when contrasted with the basemap color.

var layer = new FeatureLayer({
  url: "https://services.arcgis.com/V6ZHFr6zdgNZuVG0/arcgis/rest/services/US_county_crops_2007_clean/FeatureServer/0"
});

var typeParams = {
  layer: layer,
  basemap: map.basemap,
  field: "DOM_CROP_ACRES",
  legendOptions: {
    title: "Dominant crop in harvested acres by county (2007)"
  }
};

typeRendererCreator.createRenderer(typeParams)
  .then(function(response) {

    // set the renderer to the layer and add it to the map

    layer.renderer = response.renderer;
    map.add(layer);
  })
  .otherwise(function(err) {
    console.error("there was an error: ", err);
  });

Additional visualization samples and resources

• Generate continuous color visualization
• Generate data-driven continuous size visualization
• Generate univariate continuous size and color visualization in 3D