Add a feature layer

Learn how to access and display point, line, and polygon features in 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. You can use feature layers to store, access, and manage large amounts of geographic data for your applications. You get features from a feature layer by accessing its URL.

In this tutorial, you use URLs to access and display three different hosted feature layers:

• Trailheads (points)
• Trails (lines)
• Parks and Open Spaces (polygons)

Prerequisites

Steps

Create a new pen

1. To get started, either complete the Display a map tutorial or use this pen.

Set the API key

To access ArcGIS services, you need an API key.

1. Go to your dashboard to get an API key.

2. In CodePen, set the apiKey to your key, so it can be used to access basemap layer and location services.

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   esriConfig.apiKey = "YOUR_API_KEY";
   const map = new Map({
     basemap: "arcgis-topographic" // Basemap layer service
   });

Add modules

1. In the require statement, add the FeatureLayer module.

   More info

   The ArcGIS API for JavaScript uses AMD modules. The require function is used to load modules so they can be used in the main function. It's important to keep the module references and function parameters in the same order.

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     <script>
     require([
       "esri/config",
       "esri/Map",
       "esri/views/MapView",
   
       "esri/layers/FeatureLayer"
   
     ], function(esriConfig,Map, MapView, FeatureLayer) {
   
     });
   </script>
   

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Add a point feature layer

Point features are typically displayed in a feature layer on top of all other layers. Use the FeatureLayer class to reference the Trailheads URL and add features to the map.

1. Go to the Trailheads URL and browse the properties of the layer. Make note of the Name, Type, Drawing Info, and Fields properties.

2. In CodePen, create a FeatureLayer and set the url property.

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     const view = new MapView({
       container: "viewDiv",
       map: map,
       center: [-118.80543,34.02700],
       zoom: 13
     });
   
   //Trailheads feature layer (points)
     const trailheadsLayer = new FeatureLayer({
       url: "https://services3.arcgis.com/GVgbJbqm8hXASVYi/arcgis/rest/services/Trailheads/FeatureServer/0"
     });
   

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3. Add trailheadsLayer to the map.

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   //Trailheads feature layer (points)
     const trailheadsLayer = new FeatureLayer({
       url: "https://services3.arcgis.com/GVgbJbqm8hXASVYi/arcgis/rest/services/Trailheads/FeatureServer/0"
     });
   
     map.add(trailheadsLayer);
   

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4. Run the app to view the Trailheads layer in the map.

Add a line feature layer

Line features are typically displayed in a feature layer before points. Use the FeatureLayer class to reference the Trails URL and add features to the map.

1. Go to the Trails URL and browse the properties of the layer. Make note of the Name, Type, Drawing Info, and Fields properties.

2. In CodePen, create a FeatureLayer and set the url property.

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     map.add(trailheadsLayer);
   
   //Trails feature layer (lines)
     const trailsLayer = new FeatureLayer({
       url: "https://services3.arcgis.com/GVgbJbqm8hXASVYi/arcgis/rest/services/Trails/FeatureServer/0"
     });
   

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3. Add trailsLayer to the map with an index of 0. This ensures that the layer is added to the top of the array and is drawn before trailheadsLayer.

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   //Trails feature layer (lines)
     const trailsLayer = new FeatureLayer({
       url: "https://services3.arcgis.com/GVgbJbqm8hXASVYi/arcgis/rest/services/Trails/FeatureServer/0"
     });
   
     map.add(trailsLayer, 0);
   

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4. Run the app to view the Trails layer in the map.

Add a polygon feature layer

Polygon features are typically displayed in a feature layer before lines. Use the FeatureLayer class to reference the Parks and Open Spaces URL and add features to the map.

1. Go to the Parks and Open Spaces URL and browse the properties of the layer. Make note of the Name, Type, Drawing Info, and Fields properties.

2. In CodePen, create a FeatureLayer and set the url property.

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     map.add(trailsLayer, 0);
   
   // Parks and open spaces (polygons)
     const parksLayer = new FeatureLayer({
       url: "https://services3.arcgis.com/GVgbJbqm8hXASVYi/arcgis/rest/services/Parks_and_Open_Space/FeatureServer/0"
     });
   

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3. Add parksLayer to the map with an index of 0. This ensures that the layer is added to the top of the array and is drawn before trailsLayer.

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   // Parks and open spaces (polygons)
     const parksLayer = new FeatureLayer({
       url: "https://services3.arcgis.com/GVgbJbqm8hXASVYi/arcgis/rest/services/Parks_and_Open_Space/FeatureServer/0"
     });
   
     map.add(parksLayer, 0);
   

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Run the app

In CodePen, run your code to display the map.

The map view should display all three feature layers in the map. The map view draws the map in following order:

1. Topographic basemap layer
2. Parks and Open Spaces (polygons)
3. Trails (lines)
4. Trailheads (points)

It is important to add feature layers in the correct order so that features are displayed correctly (not overlapping) and so you can interact with the features.

What's next?

Learn how to use additional API features and ArcGIS services in these tutorials:

• Import data as a feature layer
• Create a new feature layer
• Display a pop-up
• Style a feature layer
• Query a feature layer (SQL)