Time-based query

View inMAUIUWPWPFWinUIView on GitHub

Query data using a time extent.

Image of time-based query

Use case

This workflow can be used to return records that are between a specified start and end date. For example, records of Canada goose sightings over time could be queried to only show sightings during the winter migration time period.

How to use the sample

Run the sample, and a subset of records will be displayed on the map.

How it works

  1. An instance of ServiceFeatureTable is created by passing a URL to the REST endpoint of a time-enabled service. Time-enabled services will have TimeInfo defined in the service description. This information is specified in ArcMap or ArcGIS Pro prior to publishing the service.
  2. The feature request mode of the ServiceFeatureTable is set to ManualCache, so that the developer can control how and when the feature table is populated with data.
  3. A FeatureLayer is created by passing in the instance of the ServiceFeatureTable.
  4. A TimeExtent object is created by specifying start and end date/time objects.
  5. A QueryParmaters object is created with the TimeExtent.
  6. ServiceFeatureTable.PopulateFromService is executed by passing in the QueryParameters.
  7. The feature table is populated with data that matches the provided query.

Relevant API

  • QueryParameters
  • ServiceFeatureTable.PopulateFromService
  • TimeExtent

About the data

This sample uses Atlantic hurricane data from the year 2000. The data is from the National Hurricane Center (NOAA / National Weather Service).

Tags

query, time, time extent

Sample Code

TimeBasedQuery.xaml.csTimeBasedQuery.xaml.csTimeBasedQuery.xaml
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// 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;
using Esri.ArcGISRuntime.Data;
using Esri.ArcGISRuntime.Mapping;
using System;

namespace ArcGIS.WinUI.Samples.TimeBasedQuery
{
    [ArcGIS.Samples.Shared.Attributes.Sample(
        name: "Time-based query",
        category: "Layers",
        description: "Query data using a time extent.",
        instructions: "Run the sample, and a subset of records will be displayed on the map.",
        tags: new[] { "query", "time", "time extent" })]
    public partial class TimeBasedQuery
    {
        // Hold a URI pointing to the feature service
        private Uri _serviceUri = new Uri("https://sampleserver6.arcgisonline.com/arcgis/rest/services/Hurricanes/MapServer/0");

        // Hold a reference to the feature table used by the sample
        private ServiceFeatureTable _myFeatureTable;

        public TimeBasedQuery()
        {
            InitializeComponent();

            // Initialize the map
            Initialize();
        }

        private void Initialize()
        {
            // Create a new map with oceans basemap
            Map myMap = new Map(BasemapStyle.ArcGISOceans);

            // Create feature table for the hurricane feature service
            _myFeatureTable = new ServiceFeatureTable(_serviceUri)
            {
                // Define the request mode
                FeatureRequestMode = FeatureRequestMode.ManualCache
            };

            // When feature table is loaded, populate data
            _myFeatureTable.LoadStatusChanged += OnLoadedPopulateData;

            // Create FeatureLayer that uses the created table
            FeatureLayer myFeatureLayer = new FeatureLayer(_myFeatureTable);

            // Add created layer to the map
            myMap.OperationalLayers.Add(myFeatureLayer);

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

        private async void OnLoadedPopulateData(object sender, LoadStatusEventArgs e)
        {
            // If layer isn't loaded, do nothing
            if (e.Status != LoadStatus.Loaded) { return; }

            // Create new query object that contains a basic 'include everything' clause
            QueryParameters queryParameters = new QueryParameters()
            {
                WhereClause = "1=1"
            };

            // Create a new time extent that covers the desired interval (beginning of time to September 16th, 2000)
            TimeExtent myExtent = new TimeExtent(new DateTime(1, 1, 1), new DateTime(2000, 9, 16));

            // Apply the time extent to the query parameters
            queryParameters.TimeExtent = myExtent;

            // Create list of the fields that are returned from the service
            string[] outputFields = { "*" };

            try
            {
                // Populate feature table with the data based on query
                await _myFeatureTable.PopulateFromServiceAsync(queryParameters, true, outputFields);
            }
            catch (Exception ex)
            {
                await new MessageDialog2(ex.ToString(), "Error").ShowAsync();
            }
        }
    }
}

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