Query features with SQL | OpenLayers

Learn how to execute a SQL query to a feature layerA feature layer (server-side) is a spatially-enabled table in a feature service. All features in a feature layer share the same geometry type and set of fields.Learn more.

Make a SQL query to a feature layer using API key authentication

A feature layerA feature layer (server-side) is a spatially-enabled table in a feature service. All features in a feature layer share the same geometry type and set of fields.Learn more can contain a large number of featuresA feature is a single record, also known as a row, that represents a real-world entity. It typically contains a geometry (point, multipoint, polyline, or polygon) and attributes but it can also contain just attributes.Learn more stored in ArcGISArcGIS is the brand name for all of the desktop, server, and developer products and technologies offered by Esri.Learn more. To access a subset of the features, you can execute a SQL or spatial query, or both at the same time. You can also return the attributes, geometryA geometry is a geometric shape, such as a point, polyline, or polygon, that contains one or more coordinates and a spatial reference.Learn more, or both attributes and geometry for each record. SQL and spatial queries are useful when a feature layer is very large and you just want to access a subset of the data.

In this tutorial, you perform server-side SQL queries to return a subset of the featuresA feature is a single record, also known as a row, that represents a real-world entity. It typically contains a geometry (point, multipoint, polyline, or polygon) and attributes but it can also contain just attributes.Learn more from the LA County Parcel hosted feature layerA hosted feature layer is a hosted layer (item) in a portal that is used to manage the properties and settings of a spatially-enabled feature layer in a feature service.Learn more. The feature layer contains over 2.4 million features. The resulting featuresA feature is a single record, also known as a row, that represents a real-world entity. It typically contains a geometry (point, multipoint, polyline, or polygon) and attributes but it can also contain just attributes.Learn more are displayed as graphicsA graphic is a visual element composed of a geometry, symbol, and attributes that is displayed on a map or scene.Learn more on the map. A pop-up is also used to display feature attributes.

Prerequisites

You need an ArcGIS Location Platform or ArcGIS Online account.

Steps

Get the starter app

Select a type of authentication and follow the steps to create a new app.

Choose API key authentication if you:

Want the easiest way to get started.
Want to build public applicationsA public application is an application that allows anonymous access without requiring users to sign in with an ArcGIS account. It supports API key or app authentication.Learn more that access ArcGIS Location ServicesArcGIS Location Services, also referred to as Location Services, are services hosted by Esri that provide geospatial functionality for developing mapping applications. They include the ArcGIS Basemap Styles service, ArcGIS Static Basemap Tiles service, ArcGIS Places service, ArcGIS Geocoding service, ArcGIS Routing service, ArcGIS GeoEnrichment service, and ArcGIS Elevation service. An ArcGIS Location Platform or ArcGIS Online account is required to use the services.Learn more and secure itemsAn item, also known as a content item, is a resource stored in a portal such as a web map, hosted layer, style, script tool, file, or notebook.Learn more.
Have an ArcGIS Location Platform or ArcGIS Online account.

Choose user authentication if you:

Want to build private applications.
Require application users to sign in with their own ArcGIS accountAn ArcGIS account is an identity with a user type and set of privileges that can access specific ArcGIS products, tools, APIs, services, and resources. The main account types that can be used for development are an ArcGIS Location Platform account, ArcGIS Online account, and ArcGIS Enterprise account. ArcGIS Location Platform and ArcGIS Online accounts are also associated with a subscription.Learn more and access resources their behalf.
Have an ArcGIS Online account.

To learn more about both types of authentication, go to Authentication.

You can choose one of the following to create a new CodePen:

Option 1: Complete the Display a map tutorial; or,
Option 2: Start from the Display a map tutorial .

Set up authentication

Create a new API key credentialAPI key credentials are an item that contains the parameters used to create and manage long-lived access tokens for API key authentication. They are a type of developer credential.Learn more with the correct privileges to get an access token.

Go to the Create an API key tutorial and create an API keyAn API key is a long-lived access token created using API key credentials. They are valid for up to one year and are typically embedded directly into client applications.Learn more with the following privilege(s)Privileges are a set of permissions assigned to ArcGIS accounts, developer credentials, and applications that grant access to secure resources and functionality in ArcGIS.Learn more:
- 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 credentialsAPI key credentials are an item that contains the parameters used to create and manage long-lived access tokens for API key authentication. They are a type of developer credential.Learn more access to the layer item. Learn more in Item access privileges.

Create a new OAuth credentialOAuth credentials are an item that contains parameters required to implement user authentication or app authentication, including a client_id, client_secret, and redirect URIs. They are a type of developer credential.Learn more to register the application.

Go to the Create OAuth credentials for user authentication tutorial to create an OAuth credential.
Copy the Client ID and Redirect URL from your OAuth credentials item and paste them to a safe location. They will be used in a later step.

Set developer credentials

Use the API key or OAuth developer credentialsDeveloper credentials are a type of item in a portal that contains parameters for authentication. There are two types of developer credentials: API key credentials and OAuth credentials.Learn more so your application can access ArcGIS servicesA service, also known as an ArcGIS service, is software that supports an ArcGIS REST API and provides geospatial functionality or data. A service can be hosted by Esri or in ArcGIS Enterprise.Learn more.

Update the accessToken variable to use your API key.

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    /* Use for API key authentication */
    const accessToken = "YOUR_ACCESS_TOKEN";
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In both the index.html and callback.html files, replace YOUR_CLIENT_ID and YOUR_REDIRECT_URL with the client ID and redirect URL of your OAuth credentialsOAuth credentials are an item that contains parameters required to implement user authentication or app authentication, including a client_id, client_secret, and redirect URIs. They are a type of developer credential.Learn more.

index.html
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    /* Use for user authentication */
    const clientId = "YOUR_CLIENT_ID"; // Your client ID from OAuth credentials
    const redirectUri = ""YOUR_REDIRECT_URI""; // The redirect URL registered in your OAuth credentials
    const session = await arcgisRest.ArcGISIdentityManager.beginOAuth2({
      clientId,
      redirectUri,
      portal: "https://www.arcgis.com/sharing/rest" // Your portal URL
    });

    const accessToken = session.token;

callback.html
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    arcgisRest.ArcGISIdentityManager.completeOAuth2({
      clientId: "YOUR_CLIENT_ID", // Your client ID from OAuth credentials
      redirectUri: "YOUR_REDIRECT_URI", // The redirect URL registered in your OAuth credentials
      portal: "https://www.arcgis.com/sharing/rest" // Your portal URL
    });

Run the app and ensure you can sign in successfully.

If you are unable to sign in, make sure you have the correct redirect URL and port. This URL varies based on your application and typically takes the format of https://<server>[:port]/callback.html or http://my-arcgis-app:/auth. For example, if you are running an application on http://127.0.0.1:5500/, set http://127.0.0.1:5500/callback.html as your redirect URL in the index.html and callback.html file and your developer credential. They all have to match!

Add references

This tutorial uses ArcGIS REST JS to query the feature layerA feature layer (server-side) is a spatially-enabled table in a feature service. All features in a feature layer share the same geometry type and set of fields.Learn more, and the ol-popup library to display pop-ups.

In the <head> element, add references to the ArcGIS REST JS and ol-popup libraries.

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    <link rel="stylesheet" href="https://cdn.jsdelivr.net/npm/ol@v10.9.0/ol.css">
    <script src="https://cdn.jsdelivr.net/npm/ol@v10.9.0/dist/ol.js"></script>
    <script src="https://cdn.jsdelivr.net/npm/ol-mapbox-style@13.4.1/dist/olms.js"></script>

    <script src="https://unpkg.com/@esri/arcgis-rest-request@4/dist/bundled/request.umd.js"></script>
    <script
      src="https://unpkg.com/@esri/arcgis-rest-feature-service@4/dist/bundled/feature-service.umd.js"></script>
    <script src="https://unpkg.com/ol-popup@5.1.1/dist/ol-popup.js"></script>
    <link rel="stylesheet" href="https://unpkg.com/ol-popup@5.1.1/src/ol-popup.css">
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Create a SQL selector

ArcGIS feature layersA feature layer (server-side) is a spatially-enabled table in a feature service. All features in a feature layer share the same geometry type and set of fields.Learn more support a standard SQL query where clause. Use an HTML select element to provide a list of SQL queries for the LA County Parcel feature layer.

Create a select element containing an option element for each where clause.

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  <body>
    <div id="map"></div>

    <select id="query-select">
      <option value="" selected>Choose a WHERE clause...</option>
      <option value="UseType = 'Residential'">UseType = 'Residential'</option>
      <option value="UseType = 'Government'">UseType = 'Government'</option>
      <option value="UseType = 'Irrigated Farm'">UseType = 'Irrigated Farm'</option>
      <option value="TaxRateArea = 10853">TaxRateArea = 10853</option>
      <option value="TaxRateArea = 10860">TaxRateArea = 10860</option>
      <option value="TaxRateArea = 08637">TaxRateArea = 08637</option>
      <option value="Roll_LandValue > 1000000">Roll_LandValue &gt; 1000000</option>
      <option value="Roll_LandValue < 1000000">Roll_LandValue &lt; 1000000</option>
    </select>
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Add styling to position the select element in the top right.

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    <style>
    html,
    body,
    #map {
      padding: 0;
      margin: 0;
      height: 100%;
      width: 100%;
      font-family: Arial, Helvetica, sans-serif;
      font-size: 14px;
      color: #323232;
    }


    #query-select {
      position: absolute;
      top: 20px;
      right: 20px;
      padding: 4px 8px;
      font-size: 16px;
      border-radius: 0;
      /* Causes more uniform appearance across browsers. */
    }

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Add parcel layer

Parcels returned by the query are simple GeoJSONGeoJSON is an open standard for representing geographic information in a JSON file. It is commonly used for sharing data between web services or manipulating vector data in the browser.Learn more polygonsA polygon is a type of geometry containing an array of rings and a spatial reference. Each ring contains an array of point coordinates, where the first and last point are the same.Learn more. You will create a Vector layer to display them.

Create a Vector layer and save it to a parcelLayer variable. Add it to the map with map.addLayer.

As you are not passing a style parameter, the default styling for polygons will be used. See the OpenLayers documentation for more details.

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    const basemapId = "arcgis/navigation";
    const basemapURL = `https://basemapstyles-api.arcgis.com/arcgis/rest/services/styles/v2/styles/${basemapId}?token=${accessToken}`;

    const parcelLayer = new ol.layer.Vector();

    olms.apply(map, basemapURL).then((map) => {

      map.addLayer(parcelLayer);

      // Add Esri attribution
      // Learn more in https://esriurl.com/attribution
      const source = map.getLayers().item(0).getSource();
      const poweredByEsriString = "Powered by <a href='https://www.esri.com/en-us/home' target='_blank'>Esri</a> | ";

      const attributionFn = source.getAttributions();
      if (attributionFn) {
        source.setAttributions((ViewStateLayerStateExtent) => {
          return [poweredByEsriString, ...attributionFn(ViewStateLayerStateExtent)];
        });
      } else source.setAttributions(poweredByEsriString);

    });
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Create the query

Use the ArcGIS REST JS queryFeatures method to find features in the LA County Parcels feature layerA feature layer (client-side) is a data layer that can access and display features from a feature service that has the same type of geometry and attribute fields.Learn more that match the selected where clause.

To limit the query results to the visible extentAn extent is a bounding rectangle with points that delineate an area for a map or scene.Learn more of the Map, you can set the queryFeatures geometry property. To do so your function will take a geometry object in the required esriGeometryEnvelope format of [minx, miny, maxx, maxy]. This confines the SQL query to the geographic bounds (extent) of the map.

When the matching parcels are returned, create a new Vector source using a GeoJSON feature format, to update your parcelsLayer Vector layer.

Create a function called executeQuery with whereClause and geometry parameters. Inside, create a new arcgisRest.ApiKeyManager to access the feature service. Call arcgisRest.queryFeatures. Pass the geometry and geometryType. Specify GeoJSONGeoJSON is an open standard for representing geographic information in a JSON file. It is commonly used for sharing data between web services or manipulating vector data in the browser.Learn more as the return type, requesting returnGeometry and specific outFields. All of the featuresA feature is a single record, also known as a row, that represents a real-world entity. It typically contains a geometry (point, multipoint, polyline, or polygon) and attributes but it can also contain just attributes.Learn more within the geometryA geometry is a geometric shape, such as a point, polyline, or polygon, that contains one or more coordinates and a spatial reference.Learn more will be returned with attributeAttributes are fields and values for a single feature or non-spatial record. They are typically stored in a database or service such as a feature service.Learn more information set by the outFields property.

There are many other spatial relationships that you can specify with spatialRel. For example, you can use esriSpatialRelContains to only return parcels completely within the viewport. See the ArcGIS services reference for details.

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      map.addLayer(parcelLayer);

      // Add Esri attribution
      // Learn more in https://esriurl.com/attribution
      const source = map.getLayers().item(0).getSource();
      const poweredByEsriString = "Powered by <a href='https://www.esri.com/en-us/home' target='_blank'>Esri</a> | ";

      const attributionFn = source.getAttributions();
      if (attributionFn) {
        source.setAttributions((ViewStateLayerStateExtent) => {
          return [poweredByEsriString, ...attributionFn(ViewStateLayerStateExtent)];
        });
      } else source.setAttributions(poweredByEsriString);

    });

    function executeQuery(whereClause, geometry) {
      arcgisRest
        .queryFeatures({
          url: "https://services3.arcgis.com/GVgbJbqm8hXASVYi/arcgis/rest/services/LA_County_Parcels/FeatureServer/0",
          geometry: geometry,
          geometryType: "esriGeometryEnvelope",
          inSR: 4326, // EPSG:4326 uses latitudes and longitudes
          spatialRel: "esriSpatialRelIntersects",
          where: whereClause,

          f: "geojson",
          returnGeometry: true,
          outFields: ["APN", "UseType", "TaxRateCity", " Roll_LandValue"]
        })

    }
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Add a response handler. Inside, create a GeoJSON feature format. Use it to read features from the response to a new Vector source.

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    function executeQuery(whereClause, geometry) {
      arcgisRest
        .queryFeatures({
          url: "https://services3.arcgis.com/GVgbJbqm8hXASVYi/arcgis/rest/services/LA_County_Parcels/FeatureServer/0",
          geometry: geometry,
          geometryType: "esriGeometryEnvelope",
          inSR: 4326, // EPSG:4326 uses latitudes and longitudes
          spatialRel: "esriSpatialRelIntersects",
          where: whereClause,

          f: "geojson",
          returnGeometry: true,
          outFields: ["APN", "UseType", "TaxRateCity", " Roll_LandValue"]
        })

        .then((response) => {
          const geojson = new ol.format.GeoJSON({
            defaultDataProjection: "EPSG:4326",
            featureProjection: "EPSG:3857"
          });

          let newSource = new ol.source.Vector({
            features: geojson.readFeatures(response),

          });
          parcelLayer.setSource(newSource);
        });

    }
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Add the data attributionData attribution is the requirement to display the names of data source providers in all applications when accessing ArcGIS content, layers, or services.Learn more for the feature layer source.

Go to the LA County Parcels itemAn item, also known as a content item, is a resource stored in a portal such as a web map, hosted layer, style, script tool, file, or notebook.Learn more.
Scroll down to the Acknowledgments section and copy its value.

Paste the copied value to the attributions property.

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    function executeQuery(whereClause, geometry) {
      arcgisRest
        .queryFeatures({
          url: "https://services3.arcgis.com/GVgbJbqm8hXASVYi/arcgis/rest/services/LA_County_Parcels/FeatureServer/0",
          geometry: geometry,
          geometryType: "esriGeometryEnvelope",
          inSR: 4326, // EPSG:4326 uses latitudes and longitudes
          spatialRel: "esriSpatialRelIntersects",
          where: whereClause,

          f: "geojson",
          returnGeometry: true,
          outFields: ["APN", "UseType", "TaxRateCity", " Roll_LandValue"]
        })

        .then((response) => {
          const geojson = new ol.format.GeoJSON({
            defaultDataProjection: "EPSG:4326",
            featureProjection: "EPSG:3857"
          });

          let newSource = new ol.source.Vector({
            features: geojson.readFeatures(response),

            // Attribution text retrieved from https://arcgis.com/home/item.html?id=a6fdf2ee0e454393a53ba32b9838b303
            attributions: ["| County of Los Angeles Office of the Assessor"]

          });
          parcelLayer.setSource(newSource);
        });

    }
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Execute the query

The executeQuery function needs to execute when you select an option from the select control. You achieve this by adding a change event handler. You can access the chosen where clause with the value property of the select element.

You need to calculate the extentAn extent is a bounding rectangle with points that delineate an area for a map or scene.Learn more of the current map view in latitude and longitude. You can use View.calculateExtent to get the extent, and proj.transformExtent to convert it to the EPSG:4326 spatial referenceA spatial reference is a set of parameters, typically defined by a WKID, that define the coordinate system and spatial properties for geographic data. Applications use a spatial reference to correctly display the position of geographic data in a map or scene.Learn more.

Add a change event handler to the select element. Inside, use View.calculateExtent and ol.proj.transformExtent to calculate the viewport extentAn extent is a bounding rectangle with points that delineate an area for a map or scene.Learn more. Call executeQuery with the extent and where clause.

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          let newSource = new ol.source.Vector({
            features: geojson.readFeatures(response),

            // Attribution text retrieved from https://arcgis.com/home/item.html?id=a6fdf2ee0e454393a53ba32b9838b303
            attributions: ["| County of Los Angeles Office of the Assessor"]

          });
          parcelLayer.setSource(newSource);
        });

    }

    // Listen for changes
    const select = document.getElementById("query-select");
    select.addEventListener("change", () => {
      const whereClause = select.value;

      const extent3857 = map.getView().calculateExtent(map.getSize());
      const extent4326 = ol.proj.transformExtent(extent3857, "EPSG:3857", "EPSG:4326");
      executeQuery(whereClause, extent4326);
    });

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At the top right, click Run.

When you select a where clause using the select control, a query will run against the feature layerA feature layer (client-side) is a data layer that can access and display features from a feature service that has the same type of geometry and attribute fields.Learn more and display all land parcels within the current viewport matching the where clause.

Add a pop-up

The parcels returned from the query contain many attributes, such as land value and land use type. You can make the parcels interactive by showing a pop-up when the user clicks on a parcel. You create a Popup to display parcel attributes. It is a type of Overlay so you add it to the map with map.addOverlay.

Create a Popup and save it to a popup variable. Add it to the map with map.addOverlay.

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      const extent3857 = map.getView().calculateExtent(map.getSize());
      const extent4326 = ol.proj.transformExtent(extent3857, "EPSG:3857", "EPSG:4326");
      executeQuery(whereClause, extent4326);
    });

    const popup = new Popup();
    map.addOverlay(popup);
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Create a map click event handler. Inside, use map.getFeaturesAtPixel to get the clicked parcel, if any. If there is one, use popup.show to display a pop-up containing the parcel's APN, use type, land value and taxation city.

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    const popup = new Popup();
    map.addOverlay(popup);

    map.on("click", (event) => {
      const parcel = map.getFeaturesAtPixel(event.pixel, {
        layerFilter: (l) => l === parcelLayer // don't query layers from the basemap
      })[0];
      if (parcel) {
        const message =
          `<b>Parcel ${parcel.get("APN")}</b>` +
          `<br>Type: ${parcel.get("UseType")} <br>` +
          `Land value: ${parcel.get("Roll_LandValue")} <br>` +
          `Tax Rate City: ${parcel.get("TaxRateCity")}`;
        popup.show(event.coordinate, message);
      } else {
        popup.hide();
      }
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Run the app

Run the app.

When the map displays, you should be able to use the query selector to display parcels. Click on a parcel to show a pop-up with the feature's attributes.

What's next?

Learn how to use additional location services in these tutorials:

Map with polygons and features highlighted based on spatial relationships.

Query a feature layer (spatial)

Execute a spatial query to access polygon features from a feature service.

Get global data

Query demographic information for locations around the world.

Map of New York City showing a local data summary for a defined search area.

Get local data

Query regional facts and spending trends for a study area in the United States.

A web map displaying numerous point features scattered across the United States, representing data loaded from a GeoJSON source.

Add a feature layer as GeoJSON

Display and style GeoJSON features from a feature service.

Map of Malibu, California showing trails, trailheads, and parks using colors and icons.

Style a feature layer

Use data-driven styling to apply symbol colors and styles to feature layers.