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Use a geoprocessing service and a set of features to identify statistically significant hot spots and cold spots.
Use case
This tool identifies statistically significant spatial clusters of high values (hot spots) and low values (cold spots). For example, a hotspot analysis based on the frequency of 911 calls within a set region.
How to use the sample
Select a date range (between 1998-01-01 and 1998-05-31) from the dialog and tap on Analyze. The results will be shown on the map upon successful completion of the GeoprocessingJob.
How it works
Create a GeoprocessingTask with the URL set to the endpoint of a geoprocessing service.
Create a query string with the date range as an input of GeoprocessingParameters.
Use the GeoprocessingTask to create a GeoprocessingJob with the GeoprocessingParameters instance.
Start the GeoprocessingJob and wait for it to complete and return a GeoprocessingResult.
Get the resulting ArcGISMapImageLayer using GeoprocessingResult.MapImageLayer.
Add the layer to the map's operational layers.
Relevant API
GeoprocessingJob
GeoprocessingParameters
GeoprocessingResult
GeoprocessingTask
Tags
analysis, density, geoprocessing, hot spots, hotspots
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// Copyright 2016 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.Mapping;
using Esri.ArcGISRuntime.Tasks;
using Esri.ArcGISRuntime.Tasks.Geoprocessing;
using System;
using System.Threading.Tasks;
using System.Windows;
namespaceArcGIS.WPF.Samples.AnalyzeHotspots{
[ArcGIS.Samples.Shared.Attributes.Sample(
name: "Analyze hotspots",
category: "Geoprocessing",
description: "Use a geoprocessing service and a set of features to identify statistically significant hot spots and cold spots.",
instructions: "Select a date range (between 1998-01-01 and 1998-05-31) from the dialog and tap on Analyze. The results will be shown on the map upon successful completion of the `GeoprocessingJob`.",
tags: new[] { "analysis", "density", "geoprocessing", "hot spots", "hotspots" })]
publicpartialclassAnalyzeHotspots {
// URL for the geoprocessing serviceprivateconststring _hotspotUrl =
"https://sampleserver6.arcgisonline.com/arcgis/rest/services/911CallsHotspot/GPServer/911%20Calls%20Hotspot";
// The geoprocessing task for hot spot analysisprivate GeoprocessingTask _hotspotTask;
// The job that handles the communication between the application and the geoprocessing taskprivate GeoprocessingJob _hotspotJob;
publicAnalyzeHotspots() {
InitializeComponent();
// Create the UI, setup the control references and execute initialization _ = Initialize();
}
privateasync Task Initialize() {
// Create a map with a topographic basemap MyMapView.Map = new Map(BasemapStyle.ArcGISTopographic);
try {
// Create a new geoprocessing task _hotspotTask = await GeoprocessingTask.CreateAsync(new Uri(_hotspotUrl));
}
catch (Exception e)
{
MessageBox.Show(e.ToString(), "Error");
}
}
privateasyncvoidOnAnalyzeHotspotsClicked(object sender, RoutedEventArgs e) {
// Clear any existing results MyMapView.Map.OperationalLayers.Clear();
// Show the waiting indication ShowBusyOverlay();
// Get the 'from' and 'to' dates from the date pickers for the geoprocessing analysis DateTime myFromDate = FromDate.SelectedDate.Value;
DateTime myToDate = ToDate.SelectedDate.Value;
// The end date must be at least one day after the start dateif (myToDate <= myFromDate.AddDays(1))
{
// Show error message MessageBox.Show(
"Please select valid time range. There has to be at least one day in between To and From dates.",
"Invalid date range");
// Remove the waiting ShowBusyOverlay(false);
return;
}
// Create the parameters that are passed to the used geoprocessing task GeoprocessingParameters myHotspotParameters = new GeoprocessingParameters(GeoprocessingExecutionType.AsynchronousSubmit);
// Construct the date querystring myQueryString = string.Format("(\"DATE\" > date '{0:yyyy-MM-dd} 00:00:00' AND \"DATE\" < date '{1:yyyy-MM-dd} 00:00:00')", myFromDate, myToDate);
// Add the query that contains the date range used in the analysis myHotspotParameters.Inputs.Add("Query", new GeoprocessingString(myQueryString));
// Create job that handles the communication between the application and the geoprocessing task _hotspotJob = _hotspotTask.CreateJob(myHotspotParameters);
try {
// Execute the geoprocessing analysis and wait for the results GeoprocessingResult myAnalysisResult = await _hotspotJob.GetResultAsync();
// Add results to a map using map server from a geoprocessing task// Load to get access to full extentawait myAnalysisResult.MapImageLayer.LoadAsync();
// Add the analysis layer to the map view MyMapView.Map.OperationalLayers.Add(myAnalysisResult.MapImageLayer);
// Zoom to the resultsawait MyMapView.SetViewpointAsync(new Viewpoint(myAnalysisResult.MapImageLayer.FullExtent));
}
catch (TaskCanceledException)
{
// This is thrown if the task is canceled. Ignore. }
catch (Exception ex)
{
// Display error messages if the geoprocessing task failsif (_hotspotJob.Status == JobStatus.Failed && _hotspotJob.Error != null)
MessageBox.Show("Executing geoprocessing failed. " + _hotspotJob.Error.Message, "Geoprocessing error");
else MessageBox.Show("An error occurred. " + ex, "Sample error");
}
finally {
// Remove the waiting ShowBusyOverlay(false);
}
}
privatevoidOnCancelTaskClicked(object sender, RoutedEventArgs e) {
// Cancel current geoprocessing jobif (_hotspotJob.Status == JobStatus.Started)
_hotspotJob.CancelAsync();
// Hide the waiting indication ShowBusyOverlay(false);
}
privatevoidShowBusyOverlay(bool visibility = true) {
// Function to toggle the visibility of interaction with the GUI for the user to// specify dates for the hot spot analysis. When the analysis is running, the GUI// for changing the dates is 'grayed-out' and the progress bar with a cancel// button (aka. waiting object) becomes active.if (visibility)
{
// The geoprocessing task is processing. The busyOverly is present. BusyOverlay.Visibility = Visibility.Visible;
Progress.IsIndeterminate = true;
}
else {
// The user can interact with the date pickers. The waiting is invisible. BusyOverlay.Visibility = Visibility.Collapsed;
Progress.IsIndeterminate = false;
}
}
}
}