Learn how to use renderers to apply data-driven styling to feature layers.
A feature layer is a dataset in a hosted feature service. Each feature layer contains features with a single geometry type (point, line, or polygon), and a set of attributes. Feature layers can be styled on the client-side with a renderer. Renderers are responsible for using attribute values to apply the appropriate symbol to each feature when the layer is drawn. Renderers can be used with visual variables and expressions to create more complex, data-driven visualizations.
In this tutorial, you will use three different renderers to style three hosted feature layers.
Prerequisites
Steps
Create a new pen
- To get started, either complete the Display a map tutorial or .
Get an access token
You need an access token with the correct privileges to access the location services used in this tutorial.
- Go to the Create an API key tutorial and create an API key with the following privilege(s):
- Privileges
- Location services > Basemaps
- Item access
- Note: If you are using your own custom data layer for this tutorial, you need to grant the API key credentials access to the layer item. Learn more in Item access privileges.
- Privileges
- In CodePen, set
esri
to your access token.Config.api Key Use dark colors for code blocks var esriConfig = { apiKey: "YOUR_ACCESS_TOKEN" };
To learn about other ways to get an access token, go to Types of authentication.
Add modules
-
In the
require
statement, add theFeature
module.Layer The ArcGIS Maps SDK for JavaScript is available as AMD modules and ES modules, but this tutorial is based on AMD. The AMD
require
function uses references to determine which modules will be loaded – for example, you can specify"esri/layers/
for loading the FeatureLayer module. After the modules are loaded, they are passed as parameters (e.g.Feature Layer" Feature
) to the callback function where they can be used in your application. It is important to keep the module references and callback parameters in the same order. To learn more about the API's different modules visit the Overview Guide page.Layer Use dark colors for code blocks require([ "esri/config", "esri/Map", "esri/views/MapView", "esri/layers/FeatureLayer" ], function(esriConfig, Map, MapView, FeatureLayer ) {
Style trailheads (points)
Use the Simple
, Picture
, and Label
classes to style the points with an image, and then define label attributes to display for the Trailheads feature layer.
-
Create a
trailheads
and define it as aRenderer simple
renderer. Set thesymbol
property to draw a hiker image accessed from itsurl
.Use dark colors for code blocks const view = new MapView({ container: "viewDiv", map: map, center: [-118.80543,34.02700], //Longitude, latitude zoom: 13 }); const trailheadsRenderer = { "type": "simple", "symbol": { "type": "picture-marker", "url": "http://static.arcgis.com/images/Symbols/NPS/npsPictograph_0231b.png", "width": "18px", "height": "18px" } }
-
Create a
trailheads
and set theLabels symbol
property to draw a label with theTRL
._NAME Use dark colors for code blocks const trailheadsRenderer = { "type": "simple", "symbol": { "type": "picture-marker", "url": "http://static.arcgis.com/images/Symbols/NPS/npsPictograph_0231b.png", "width": "18px", "height": "18px" } } const trailheadsLabels = { symbol: { type: "text", color: "#FFFFFF", haloColor: "#5E8D74", haloSize: "2px", font: { size: "12px", family: "Noto Sans", style: "italic", weight: "normal" } }, labelPlacement: "above-center", labelExpressionInfo: { expression: "$feature.TRL_NAME" } };
-
Create a
trailheads
Feature
. Set theLayer url
property to access its URL endpoint. Set therenderer
andlabeling
before addingInfo trailheads
to themap
. The feature layer will autocast therenderer
andlabeling
to create class instances of the objects.Info Use dark colors for code blocks labelPlacement: "above-center", labelExpressionInfo: { expression: "$feature.TRL_NAME" } }; // Create the layer and set the renderer const trailheads = new FeatureLayer({ url: "https://services3.arcgis.com/GVgbJbqm8hXASVYi/arcgis/rest/services/Trailheads/FeatureServer/0", renderer: trailheadsRenderer, labelingInfo: [trailheadsLabels] }); map.add(trailheads);
-
View hiker symbols with trailhead names.
Style trails (lines)
Use the Simple
and Visual
classes to style trails in the Trails feature layer. Visual variables define the attribute to use to style trails with a greater elevation gain wider compared to trails with smaller elevation changes. This is one form of data-driven visualization.
-
Create a
trails
and define it as aRenderer simple
renderer.Use dark colors for code blocks map.add(trailheads); // Define a unique value renderer and symbols const trailsRenderer = { type: "simple", symbol: { color: "#BA55D3", type: "simple-line", style: "solid" },
-
In the
visual
array, set theVariables field
toELEV
to determine line width._GAIN Use dark colors for code blocks // Define a unique value renderer and symbols const trailsRenderer = { type: "simple", symbol: { color: "#BA55D3", type: "simple-line", style: "solid" }, visualVariables: [ { type: "size", field: "ELEV_GAIN", minDataValue: 0, maxDataValue: 2300, minSize: "3px", maxSize: "7px" } ] };
-
Create a
trails
Feature
. Set theLayer url
to access its URL endpoint. Set therenderer
andopacity
properties before addingtrails
to themap
. The feature layer will autocast therenderer
a create class instances of the object.Use dark colors for code blocks visualVariables: [ { type: "size", field: "ELEV_GAIN", minDataValue: 0, maxDataValue: 2300, minSize: "3px", maxSize: "7px" } ] }; // Create the layer and set the renderer const trails = new FeatureLayer({ url: "https://services3.arcgis.com/GVgbJbqm8hXASVYi/arcgis/rest/services/Trails/FeatureServer/0", renderer: trailsRenderer, opacity: 0.75 }); // Add the layer map.add(trails,0);
-
View trails of differing widths based on elevation gain.
Show bike-only trails (lines)
You can use a renderer and definition expression to style a subset of data from a feature layer. To style bike-only trails from the Trails feature layer, use the definition
, Simple
and Simple
classes. The layer is added on top of the existing trails layer.
-
Create a
bike
and define it as aTrails Renderer simple
renderer. Set thesymbol
to draw a line that is styled with dots in pink.Use dark colors for code blocks // Add the layer map.add(trails,0); // Add bikes only trails const bikeTrailsRenderer = { type: "simple", symbol: { type: "simple-line", style: "short-dot", color: "#FF91FF", width: "1px" } };
-
Create a
bike
Trails Feature
and set theLayer url
andrenderer
properties. Set thedefinition
(a SQL where clause) to access bike trails from the Trails feature layer before addingExpression bike
to theTrails map
. The feature layer will autocast therenderer
a create class instances of the object.Use dark colors for code blocks // Add bikes only trails const bikeTrailsRenderer = { type: "simple", symbol: { type: "simple-line", style: "short-dot", color: "#FF91FF", width: "1px" } }; const bikeTrails = new FeatureLayer({ url: "https://services3.arcgis.com/GVgbJbqm8hXASVYi/arcgis/rest/services/Trails/FeatureServer/0", renderer: bikeTrailsRenderer, definitionExpression: "USE_BIKE = 'YES'" }); map.add(bikeTrails, 1);
-
View the location of bike trails in relation to other trails.
Style open spaces (polygons)
You can use renderers to style feature layer data by unique attribute values. Use the Unique
and Simple
classes to style polygon features with different fill colors, based on the TYPE attribute in the Parks and Open Spaces feature layer.
-
Create a
create
function withFill Symbol value
andcolor
as parameters. The function will return asolid
,simple-fill
symbol for each park type.Use dark colors for code blocks map.add(bikeTrails, 1); // Add parks with a class breaks renderer and unique symbols function createFillSymbol(value, color) { return { "value": value, "symbol": { "color": color, "type": "simple-fill", "style": "solid", "outline": { "style": "none" } }, "label": value }; }
-
Create an
open
and define it asSpaces Renderer unique-value
. Set thefield
property toTYPE
. In theunique
array, set unique colors for each park type.Value Infos Use dark colors for code blocks // Add parks with a class breaks renderer and unique symbols function createFillSymbol(value, color) { return { "value": value, "symbol": { "color": color, "type": "simple-fill", "style": "solid", "outline": { "style": "none" } }, "label": value }; } const openSpacesRenderer = { type: "unique-value", field: "TYPE", uniqueValueInfos: [ createFillSymbol("Natural Areas", "#9E559C"), createFillSymbol("Regional Open Space", "#A7C636"), createFillSymbol("Local Park", "#149ECE"), createFillSymbol("Regional Recreation Park", "#ED5151") ] };
-
Create an
openspaces
Feature
. Set theLayer url
to access its URL endpoint. Set therenderer
andopacity
properties before addingopenspaces
to themap
. The feature layer will autocast therenderer
to create class instances of the object.Use dark colors for code blocks const openSpacesRenderer = { type: "unique-value", field: "TYPE", uniqueValueInfos: [ createFillSymbol("Natural Areas", "#9E559C"), createFillSymbol("Regional Open Space", "#A7C636"), createFillSymbol("Local Park", "#149ECE"), createFillSymbol("Regional Recreation Park", "#ED5151") ] }; // Create the layer and set the renderer const openspaces = new FeatureLayer({ url: "https://services3.arcgis.com/GVgbJbqm8hXASVYi/arcgis/rest/services/Parks_and_Open_Space/FeatureServer/0", renderer: openSpacesRenderer, opacity: 0.2 }); // Add the layer map.add(openspaces,0);
Run the app
In CodePen, run your code to display the map.
The completed map should display all of the layers with a unique, data-driven style.
What's next?
Learn how to use additional API features and ArcGIS services in these tutorials: