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Display a time-enabled feature layer with a time offset.
Use case
You can use a time offset to compare time periods by displaying them overlaid on the map. For example, you could show a feature layer with flu cases from December overlaid with flu cases from January to visualize the spread of the disease over time.
How to use the sample
When the sample loads, you'll see hurricane tracks visualized in red and blue. The red hurricane tracks occurred 10 days before the tracks displayed in blue. Adjust the slider to move the interval to visualize how storms progress over time.
How it works
Create a feature layer for displaying the non-offset features and apply symbology to it.
Create a second feature layer referring to the same service. Apply a 10 day time offset and unique symbology. Features displayed from this layer will have time values 10 days earlier than the values in the non-offset layer.
Apply a 10-day time extent to the map view, starting at the beginning of the data range.
When the user adjusts the slider, move the time extent. Both feature layers will filter their content for the map view's time extent.
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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.Mapping;
using Esri.ArcGISRuntime.Symbology;
using System;
using System.Threading.Tasks;
using System.Windows;
namespaceArcGIS.WPF.Samples.FeatureLayerTimeOffset{
[ArcGIS.Samples.Shared.Attributes.Sample(
name: "Feature layer time offset",
category: "MapView",
description: "Display a time-enabled feature layer with a time offset.",
instructions: "When the sample loads, you'll see hurricane tracks visualized in red and blue. The red hurricane tracks occurred 10 days before the tracks displayed in blue. Adjust the slider to move the interval to visualize how storms progress over time.",
tags: new[] { "change", "range", "time", "time extent", "time offset", "time-aware", "time-enabled" })]
publicpartialclassFeatureLayerTimeOffset {
// Hold the feature layer URIprivate Uri _featureLayerUri = new Uri("https://sampleserver6.arcgisonline.com/arcgis/rest/services/Hurricanes/MapServer/0");
// Hold a reference to the original time extentprivate TimeExtent _originalExtent;
publicFeatureLayerTimeOffset() {
InitializeComponent();
// Create the UI, setup the control references and execute initialization _ = Initialize();
}
privateasync Task Initialize() {
// Create new Map Map myMap = new Map(BasemapStyle.ArcGISOceans);
// Create the hurricanes feature layer once FeatureLayer noOffsetLayer = new FeatureLayer(_featureLayerUri);
// Apply a blue dot renderer to distinguish hurricanes without offsets SimpleMarkerSymbol blueDot = new SimpleMarkerSymbol(SimpleMarkerSymbolStyle.Circle, System.Drawing.Color.Blue, 10);
noOffsetLayer.Renderer = new SimpleRenderer(blueDot);
// Add the non-offset layer to the map myMap.OperationalLayers.Add(noOffsetLayer);
// Create the offset hurricanes feature layer FeatureLayer withOffsetLayer = new FeatureLayer(_featureLayerUri);
// Apply a red dot renderer to distinguish these hurricanes from the non-offset hurricanes SimpleMarkerSymbol redDot = new SimpleMarkerSymbol(SimpleMarkerSymbolStyle.Circle, System.Drawing.Color.Red, 10);
withOffsetLayer.Renderer = new SimpleRenderer(redDot);
// Apply the time offset (red hurricane dots will be from 10 days before the current extent) withOffsetLayer.TimeOffset = new TimeValue(10, Esri.ArcGISRuntime.ArcGISServices.TimeUnit.Days);
// Add the layer to the map myMap.OperationalLayers.Add(withOffsetLayer);
// Apply the Map to the MapView MyMapView.Map = myMap;
try {
// Ensure the no offset layer is loadedawait noOffsetLayer.LoadAsync();
// Store a reference to the original time extent _originalExtent = noOffsetLayer.FullTimeExtent;
// Update the time extent set on the map UpdateTimeExtent();
}
catch (Exception e)
{
MessageBox.Show(e.ToString(), "Error");
}
}
privatevoidMyTimeSlider_ValueChanged(object sender, System.Windows.RoutedPropertyChangedEventArgs<double> e) {
UpdateTimeExtent();
}
privatevoidUpdateTimeExtent() {
// Get the value of the sliderdoublevalue = MyTimeSlider.Value;
// Calculate the number of days that value corresponds to// 1. Get the interval TimeSpan interval = _originalExtent.EndTime - _originalExtent.StartTime;
// 2. Store the interval as daysdouble days = interval.TotalDays;
// 3. Scale the interval by the value from the sliderdouble desiredInterval = value * days;
// 4. Create a new TimeSpan TimeSpan newOffset = new TimeSpan((int)desiredInterval, 0, 0, 0);
// Determine the new starting offset DateTime newStart = _originalExtent.StartTime.DateTime.Add(newOffset);
// Determine the new ending offset DateTime newEnd = newStart.AddDays(10);
// Reset the new DateTimeOffset if it is outside of the extentif (newEnd > _originalExtent.EndTime)
{
newEnd = _originalExtent.EndTime.DateTime;
}
// Do nothing if out of boundsif (newEnd < newStart) { return; }
// Apply the new extent MyMapView.TimeExtent = new TimeExtent(newStart, newEnd);
// Update the label CurrentDateLabel.Text = string.Format("{0} - {1}", newStart.ToShortDateString(), newEnd.ToShortDateString());
}
}
}