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ArcGIS Runtime SDK for .NET

Find place

This code sample is available for these platforms:
View Sample on GitHub

Find places of interest near a location or within a specific area.

screenshot

Use case

When getting directions or looking for nearby places, users may only know what the place has ("food"), the type of place ("gym"), or the generic place name ("Starbucks"), rather than the specific address. You can get suggestions and locations for these places of interest (POIs) using a natural language query. Additionally, you can filter the results to a specific area.

How to use the sample

Choose a type of place in the first field and an area to search within in the second field. Click the Search button to show the results of the query on the map. Click on a result pin to show its name and address.

How it works

  1. Create a LocatorTask using a URL to a locator service.
  2. Find the location for an address (or city name) to build an envelope to search within:
    • Create GeocodeParameters.
    • Add return fields to the parameters' ResultAttributeNames collection. Only add a single "*" option to return all fields.
    • Call locatorTask.GeocodeAsync(locationQueryString, geocodeParameters) to get a list of GeocodeResults.
    • Use the DisplayLocation from one of the results to build an Envelope to search within.
  3. Get place of interest (POI) suggestions based on a place name query:
    • Create SuggestParameters.
    • Add "POI" to the parameters' categories collection.
    • Call locatorTask.SuggestAsync(placeQueryString, suggestParameters) to get a list of SuggestResults.
    • The SuggestResult will have a label to display in the search suggestions list.
  4. Use one of the suggestions or a user-written query to find the locations of POIs:
    • Create GeocodeParameters.
    • Set the parameters' searchArea to the envelope.
    • Call locatorTask.GeocodeAsync(suggestionLabelOrPlaceQueryString, geocodeParameters) to get a list of GeocodeResults.
    • Display the places of interest using the results' DisplayLocations.

Relevant API

  • GeocodeParameters
  • GeocodeResult
  • LocatorTask
  • SuggestParameters
  • SuggestResult

About the data

This sample uses the world locator service "https://geocode.arcgis.com/arcgis/rest/services/World/GeocodeServer".

Tags

POI, businesses, geocode, locations, locator, places of interest, point of interest, search, suggestions

Sample Code

<UserControl
    x:Class="ArcGISRuntime.UWP.Samples.FindPlace.FindPlace"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    xmlns:esri="using:Esri.ArcGISRuntime.UI.Controls">
    <Grid>
        <esri:MapView x:Name="MyMapView" />
        <Border Style="{StaticResource BorderStyle}">
            <Grid>
                <Grid.RowDefinitions>
                    <RowDefinition Height="Auto" />
                    <RowDefinition Height="Auto" />
                    <RowDefinition Height="Auto" />
                    <RowDefinition Height="Auto" />
                    <RowDefinition Height="Auto" />
                </Grid.RowDefinitions>
                <Grid.ColumnDefinitions>
                    <ColumnDefinition Width="*" />
                    <ColumnDefinition Width="*" />
                    <ColumnDefinition Width="2*" />
                </Grid.ColumnDefinitions>
                <TextBlock
                    Text="Enter a search term and a search location. Tap 'Search all' to find all results near that location. Tap 'Search in view' to restrict the search to results within the current visible extent."
                    Grid.Row="0" Grid.Column="0" Grid.ColumnSpan="3"
                    Margin="0,0,0,5"
                    FontWeight="SemiBold" TextWrapping="Wrap" TextAlignment="Justify" />
                <TextBlock Text="Search:"
                           Grid.Row="1" Grid.Column="0"
                           Margin="0,5,0,0"
                           TextAlignment="Right" FontWeight="SemiBold"
                           VerticalAlignment="Center" />
                <TextBlock Text="Location:"
                           Grid.Row="2" Grid.Column="0"
                           Margin="0,5,0,0"
                           TextAlignment="Right" FontWeight="SemiBold"
                           VerticalAlignment="Center" />
                <AutoSuggestBox x:Name="SearchEntry"
                                Grid.Row="1" Grid.Column="1" Grid.ColumnSpan="2"
                                Text="Coffee"
                                Margin="5,5,0,0"
                                IsEnabled="False"
                                TextChanged="MySearchBox_TextChanged" />
                <AutoSuggestBox x:Name="LocationEntry" Text="Current Location"
                                Grid.Row="2" Grid.Column="1" Grid.ColumnSpan="2"
                                Margin="5,5,0,0"
                                IsEnabled="False"
                                TextChanged="MyLocationBox_TextChanged" />
                <Button x:Name="SearchButton"
                        Grid.Row="3" Grid.Column="0" Grid.ColumnSpan="2" HorizontalAlignment="Stretch"
                        Content="Search all"
                        Margin="0,5,2.5,0"
                        IsEnabled="False"
                        Click="SearchButton_Click" />
                <Button x:Name="SearchViewButton"
                        Grid.Row="3" Grid.Column="2" HorizontalAlignment="Stretch"
                        Content="Search in view"
                        Margin="2.5,5,0,0"
                        IsEnabled="False"
                        Click="SearchViewButton_Click" />
                <ProgressBar x:Name="ProgressBar"
                             Grid.Row="4" Grid.Column="0" Grid.ColumnSpan="3"
                             IsIndeterminate="True"
                             Margin="0,5,0,0"
                             Visibility="Collapsed" />
            </Grid>
        </Border>
    </Grid>
</UserControl>
// Copyright 2017 Esri.
//
// Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in compliance with the License.
// You may obtain a copy of the License at: http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software distributed under the License is distributed on an
// "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the License for the specific
// language governing permissions and limitations under the License.

using Esri.ArcGISRuntime.Data;
using Esri.ArcGISRuntime.Geometry;
using Esri.ArcGISRuntime.Mapping;
using Esri.ArcGISRuntime.Symbology;
using Esri.ArcGISRuntime.Tasks.Geocoding;
using Esri.ArcGISRuntime.UI;
using Esri.ArcGISRuntime.UI.Controls;
using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Reflection;
using System.Threading.Tasks;
using Windows.UI.Popups;
using Windows.UI.Xaml;
using Windows.UI.Xaml.Controls;

namespace ArcGISRuntime.UWP.Samples.FindPlace
{
    [ArcGISRuntime.Samples.Shared.Attributes.Sample(
        "Find place",
        "Search",
        "This sample demonstrates how to use geocode functionality to search for points of interest, around a location or within an extent.",
        "1. Enter a point of interest you'd like to search for (e.g. 'Starbucks')\n2. Enter a search location or accept the default 'Current Location'\n3. Select 'search all' to get all results, or press 'search view' to only get results within the current extent.")]
    [ArcGISRuntime.Samples.Shared.Attributes.EmbeddedResource(@"PictureMarkerSymbols\pin_star_blue.png")]
    public partial class FindPlace
    {
        // The LocatorTask provides geocoding services
        private LocatorTask _geocoder;

        // Service Uri to be provided to the LocatorTask (geocoder)
        private Uri _serviceUri = new Uri("https://geocode.arcgis.com/arcgis/rest/services/World/GeocodeServer");

        public FindPlace()
        {
            InitializeComponent();

            // Setup the control references and execute initialization
            Initialize();
        }

        private async void Initialize()
        {
            // Create new Map with basemap
            Map myMap = new Map(Basemap.CreateStreets());

            // Subscribe to location changed event so that map can zoom to location
            MyMapView.LocationDisplay.LocationChanged += LocationDisplay_LocationChanged;

            // Enable location display
            MyMapView.LocationDisplay.IsEnabled = true;

            // Enable tap-for-info pattern on results
            MyMapView.GeoViewTapped += MyMapView_GeoViewTapped;

            // Assign the map to the MapView
            MyMapView.Map = myMap;

            // Initialize the LocatorTask with the provided service Uri
            _geocoder = await LocatorTask.CreateAsync(_serviceUri);

            // Enable all controls now that the locator task is ready
            SearchEntry.IsEnabled = true;
            LocationEntry.IsEnabled = true;
            SearchButton.IsEnabled = true;
            SearchViewButton.IsEnabled = true;
        }

        private async void LocationDisplay_LocationChanged(object sender, Esri.ArcGISRuntime.Location.Location e)
        {
            // Return if position is null; event is raised with null location after
            if (e.Position == null) { return; }

            // Unsubscribe from further events; only want to zoom to location once
            ((LocationDisplay)sender).LocationChanged -= LocationDisplay_LocationChanged;

            // Need to use the dispatcher to interact with UI elements because this function is called from a background thread
            await Dispatcher.RunAsync(Windows.UI.Core.CoreDispatcherPriority.Normal, () =>
            {
                MyMapView.SetViewpoint(new Viewpoint(e.Position, 100000));
            });
        }

        /// <summary>
        /// Gets the map point corresponding to the text in the location textbox.
        /// If the text is 'Current Location', the returned map point will be the device's location.
        /// </summary>
        /// <param name="locationText"></param>
        /// <returns></returns>
        private async Task<MapPoint> GetSearchMapPoint(string locationText)
        {
            // Get the map point for the search text
            if (locationText != "Current Location")
            {
                // Geocode the location
                IReadOnlyList<GeocodeResult> locations = await _geocoder.GeocodeAsync(locationText);

                // return if there are no results
                if (locations.Count < 1) { return null; }

                // Get the first result
                GeocodeResult result = locations.First();

                // Return the map point
                return result.DisplayLocation;
            }
            else
            {
                // Get the current device location
                return MyMapView.LocationDisplay.Location.Position;
            }
        }

        /// <summary>
        /// Runs a search and populates the map with results based on the provided information
        /// </summary>
        /// <param name="enteredText">Results to search for</param>
        /// <param name="locationText">Location around which to find results</param>
        /// <param name="restrictToExtent">If true, limits results to only those that are within the current extent</param>
        private async void UpdateSearch(string enteredText, string locationText, bool restrictToExtent = false)
        {
            // Clear any existing markers
            MyMapView.GraphicsOverlays.Clear();

            // Return gracefully if the textbox is empty or the geocoder isn't ready
            if (String.IsNullOrWhiteSpace(enteredText) || _geocoder == null) { return; }

            // Create the geocode parameters
            GeocodeParameters parameters = new GeocodeParameters();

            // Get the MapPoint for the current search location
            MapPoint searchLocation = await GetSearchMapPoint(locationText);

            // Update the geocode parameters if the map point is not null
            if (searchLocation != null)
            {
                parameters.PreferredSearchLocation = searchLocation;
            }

            // Update the search area if desired
            if (restrictToExtent)
            {
                // Get the current map extent
                Geometry extent = MyMapView.VisibleArea;

                // Update the search parameters
                parameters.SearchArea = extent;
            }

            // Show the progress bar
            ProgressBar.Visibility = Visibility.Visible;

            // Get the location information
            IReadOnlyList<GeocodeResult> locations = await _geocoder.GeocodeAsync(enteredText, parameters);

            // Stop gracefully and show a message if the geocoder does not return a result
            if (locations.Count < 1)
            {
                ProgressBar.Visibility = Visibility.Collapsed; // 1. Hide the progress bar
                ShowStatusMessage("No results found"); // 2. Show a message
                return; // 3. Stop
            }

            // Create the GraphicsOverlay so that results can be drawn on the map
            GraphicsOverlay resultOverlay = new GraphicsOverlay();

            // Add each address to the map
            foreach (GeocodeResult location in locations)
            {
                // Get the Graphic to display
                Graphic point = await GraphicForPoint(location.DisplayLocation);

                // Add the specific result data to the point
                point.Attributes["Match_Title"] = location.Label;

                // Get the address for the point
                IReadOnlyList<GeocodeResult> addresses = await _geocoder.ReverseGeocodeAsync(location.DisplayLocation);

                // Add the first suitable address if possible
                if (addresses.Any())
                {
                    point.Attributes["Match_Address"] = addresses[0].Label;
                }

                // Add the Graphic to the GraphicsOverlay
                resultOverlay.Graphics.Add(point);
            }

            // Hide the progress bar
            ProgressBar.Visibility = Visibility.Collapsed;

            // Add the GraphicsOverlay to the MapView
            MyMapView.GraphicsOverlays.Add(resultOverlay);

            // Update the map viewpoint
            await MyMapView.SetViewpointGeometryAsync(resultOverlay.Extent, 50);
        }

        /// <summary>
        /// Creates and returns a Graphic associated with the given MapPoint
        /// </summary>
        private async Task<Graphic> GraphicForPoint(MapPoint point)
        {
            // Get current assembly that contains the image
            Assembly currentAssembly = GetType().GetTypeInfo().Assembly;

            // Get image as a stream from the resources
            // Picture is defined as EmbeddedResource and DoNotCopy
            Stream resourceStream = currentAssembly.GetManifestResourceStream(
                "ArcGISRuntime.Resources.PictureMarkerSymbols.pin_star_blue.png");

            // Create new symbol using asynchronous factory method from stream
            PictureMarkerSymbol pinSymbol = await PictureMarkerSymbol.CreateAsync(resourceStream);
            pinSymbol.Width = 60;
            pinSymbol.Height = 60;
            // The image is a pin; offset the image so that the pinpoint
            //     is on the point rather than the image's true center
            pinSymbol.LeaderOffsetX = 30;
            pinSymbol.OffsetY = 14;
            return new Graphic(point, pinSymbol);
        }

        /// <summary>
        /// Shows a callout for any tapped graphics
        /// </summary>
        private async void MyMapView_GeoViewTapped(object sender, GeoViewInputEventArgs e)
        {
            // Search for the graphics underneath the user's tap
            IReadOnlyList<IdentifyGraphicsOverlayResult> results = await MyMapView.IdentifyGraphicsOverlaysAsync(e.Position, 12, false);

            // Clear callouts and return if there was no result
            if (results.Count < 1 || results.First().Graphics.Count < 1) { MyMapView.DismissCallout(); return; }

            // Get the first graphic from the first result
            Graphic matchingGraphic = results.First().Graphics.First();

            // Get the title; manually added to the point's attributes in UpdateSearch
            string title = matchingGraphic.Attributes["Match_Title"] as String;

            // Get the address; manually added to the point's attributes in UpdateSearch
            string address = matchingGraphic.Attributes["Match_Address"] as String;

            // Define the callout
            CalloutDefinition calloutBody = new CalloutDefinition(title, address);

            // Show the callout on the map at the tapped location
            MyMapView.ShowCalloutAt(e.Location, calloutBody);
        }

        /// <summary>
        /// Returns a list of suggestions based on the input search text and limited by the specified parameters
        /// </summary>
        /// <param name="searchText">Text to get suggestions for</param>
        /// <param name="location">Location around which to look for suggestions</param>
        /// <param name="poiOnly">If true, restricts suggestions to only Points of Interest (e.g. businesses, parks),
        /// rather than all matching results</param>
        /// <returns>List of suggestions as strings</returns>
        private async Task<List<string>> GetSuggestResults(string searchText, string location = "", bool poiOnly = false)
        {
            // Quit if string is null, empty, or whitespace
            if (String.IsNullOrWhiteSpace(searchText))
            {
                return new List<string>();
            }

            // Quit if the geocoder isn't ready
            if (_geocoder == null)
            {
                return new List<string>();
            }

            // Create geocode parameters
            SuggestParameters parameters = new SuggestParameters();

            // Restrict suggestions to points of interest if desired
            if (poiOnly) { parameters.Categories.Add("POI"); }

            // Set the location for the suggest parameters
            if (!String.IsNullOrWhiteSpace(location))
            {
                // Get the MapPoint for the current search location
                MapPoint searchLocation = await GetSearchMapPoint(location);

                // Update the geocode parameters if the map point is not null
                if (searchLocation != null)
                {
                    parameters.PreferredSearchLocation = searchLocation;
                }
            }

            // Get the updated results from the query so far
            IReadOnlyList<SuggestResult> results = await _geocoder.SuggestAsync(searchText, parameters);

            // Return the list
            return results.Select(result => result.Label).ToList();
        }

        /// <summary>
        /// Method abstracts the platform-specific message box functionality to maximize re-use of common code
        /// </summary>
        /// <param name="message">Text of the message to show.</param>
        private async void ShowStatusMessage(string message)
        {
            // Display the message to the user
            MessageDialog dialog = new MessageDialog(message);
            await dialog.ShowAsync();
        }

        /// <summary>
        /// Method used to keep the suggestions up-to-date for the search box
        /// </summary>
        private async void MySearchBox_TextChanged(AutoSuggestBox sender, AutoSuggestBoxTextChangedEventArgs args)
        {
            // Dismiss callout, if any
            UserInteracted();

            // Get the current text
            string searchText = SearchEntry.Text;

            // Get the current search location
            string locationText = LocationEntry.Text;

            // Convert the list into a usable format for the suggest box
            List<string> results = await GetSuggestResults(searchText, locationText, true);

            // Quit if there are no results
            if (!results.Any()) { return; }

            // Update the list of options
            SearchEntry.ItemsSource = results;
        }

        /// <summary>
        /// Method used to keep the suggestions up-to-date for the location box
        /// </summary>
        private async void MyLocationBox_TextChanged(AutoSuggestBox sender, AutoSuggestBoxTextChangedEventArgs args)
        {
            // Dismiss callout, if any
            UserInteracted();

            // Get the current text
            string searchText = LocationEntry.Text;

            // Get the results
            List<string> results = await GetSuggestResults(searchText);

            // Quit if there are no results
            if (!results.Any())
            {
                return;
            }

            // Add a 'current location' option to the list
            results.Insert(0, "Current Location");

            // Update the list of options
            LocationEntry.ItemsSource = results;
        }

        /// <summary>
        /// Method called to start a search that is restricted to results within the current extent
        /// </summary>
        private void SearchViewButton_Click(object sender, RoutedEventArgs e)
        {
            // Dismiss callout, if any
            UserInteracted();

            // Get the search text
            string searchText = SearchEntry.Text;

            // Get the location text
            string locationText = LocationEntry.Text;

            // Run the search
            UpdateSearch(searchText, locationText, true);
        }

        /// <summary>
        /// Method called to start an unrestricted search
        /// </summary>
        private void SearchButton_Click(object sender, RoutedEventArgs e)
        {
            // Dismiss callout, if any
            UserInteracted();

            // Get the search text
            string searchText = SearchEntry.Text;

            // Get the location text
            string locationText = LocationEntry.Text;

            // Run the search
            UpdateSearch(searchText, locationText);
        }

        /// <summary>
        /// Method to handle hiding the callout, should be called by all UI event handlers
        /// </summary>
        private void UserInteracted()
        {
            // Hide the callout
            MyMapView.DismissCallout();
        }
    }
}