Find features in a sublayer based on attributes and location.
Use case
Sublayers of an ArcGISMapImageLayer may expose a ServiceFeatureTable through a table property. This allows you to perform the same queries available when working with a table from a FeatureLayer: attribute query, spatial query, statistics query, query for related features, etc. An image layer with a sublayer of counties can be queried by population to only show those above a minimum population.
How to use the sample
Specify a minimum population in the input field (values under 1810000 will produce a selection in all layers) and click the query button to query the sublayers in the current view extent. After a short time, the results for each sublayer will appear as graphics.
How it works
Create an ArcGISMapImageLayer object using the URL of an image service.
After loading the layer, get the sublayer you want to query with (ArcGISMapImageSublayer) layer.mapImageSublayers.get(index).
Load the sublayer, and then get its ServiceFeatureTable with sublayer.table.
Create QueryParameters. You can use queryParameters.whereClause = sqlQueryString to query against a table attribute and/or set queryParameters.geometry = extent to limit the results to an area of the map.
Call sublayerTable.queryFeatures(queryParameters) to get a FeatureQueryResult with features matching the query. The result is an iterable of features.
Relevant API
ArcGISMapImageLayer
ArcGISMapImageLayer.loadTablesAndLayers
ArcGISMapImageSublayer
ArcGISMapImageSublayer.table
QueryParameters
ServiceFeatureTable
Additional information
An ArcGISMapImageSublayer must be loaded before accessing its metadata or table. Use ArcGISMapImageLayer.loadTablesAndLayers to recursively load all sublayers and tables associated with a map image layer. Some sublayers do not have an associated table (group layers, for example) and some may not support specific types of queries. Consult the map service metadata for details.
Tags
MapServer, Query, Sublayer, Table
Sample Code
QueryMapImageSublayer.qml
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// [WriteFile Name=QueryMapImageSublayer, Category=Layers]// [Legal]// Copyright 2018 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.// [Legal]import QtQuick
import QtQuick.Controls
import Esri.ArcGISRuntime
Rectangle {
id: rootRectangleclip: truewidth: 800height: 600property var citiesTableproperty var statesTableproperty var countiesTable// Declare a MapViewMapView {
id: mapViewanchors.fill: parentComponent.onCompleted: {
// Set the focus on MapView to initially enable keyboard navigation forceActiveFocus();
}
// Desclare a Map inside the MapViewMap {
// Declare a BasemapBasemap {
initStyle: Enums.BasemapStyleArcGISStreets
}
// Add a Map Image LayerArcGISMapImageLayer {
url: "https://sampleserver6.arcgisonline.com/arcgis/rest/services/USA/MapServer"// Once the layer loads, load the tables and sublayersonLoadStatusChanged: {
if (loadStatus !== Enums.LoadStatusLoaded)
return;
loadTablesAndLayers();
}
// Once tables and sublayers load, obtain the tables and connect signalsonLoadTablesAndLayersStatusChanged: {
if (loadTablesAndLayersStatus !== Enums.TaskStatusCompleted)
return;
if (mapImageSublayers.count < 4)
return;
// get the sublayer's tables citiesTable = mapImageSublayers.get(0).table;
statesTable = mapImageSublayers.get(2).table;
countiesTable = mapImageSublayers.get(3).table;
// connect to city sublayer query signal citiesTable.queryFeaturesStatusChanged.connect(()=> {
if (citiesTable.queryFeaturesStatus !== Enums.TaskStatusCompleted)
return;
// add the results as graphics addResultsAsGraphics(citiesTable.queryFeaturesResult, citySymbol);
});
// connect to county sublayer query signal countiesTable.queryFeaturesStatusChanged.connect(()=> {
if (countiesTable.queryFeaturesStatus !== Enums.TaskStatusCompleted)
return;
// add the results as graphics addResultsAsGraphics(countiesTable.queryFeaturesResult, countyFillSymbol);
});
// connect to state sublayer query signal statesTable.queryFeaturesStatusChanged.connect(()=> {
if (statesTable.queryFeaturesStatus !== Enums.TaskStatusCompleted)
return;
// add the results as graphics addResultsAsGraphics(statesTable.queryFeaturesResult, stateFillSymbol);
});
}
}
// set an initial viewpointViewpointCenter {
targetScale: 6000000Point {
x: -12716000.00y: 4170400.00spatialReference: SpatialReference { wkid: 3857 }
}
}
}
// Add a graphics overlay to show selected featuresGraphicsOverlay {
id: selectedFeaturesOverlay }
}
functionaddResultsAsGraphics(results, symbol) {
// get the iterator of featuresconst iter = results.iterator;
// add a graphic for each feature in the resultwhile (iter.hasNext) {
const feat = iter.next();
const graphic = ArcGISRuntimeEnvironment.createObject("Graphic",
{
geometry: feat.geometry,
symbol: symbol
});
selectedFeaturesOverlay.graphics.append(graphic);
}
}
Rectangle {
anchors {
fill: controlColumn
margins: -5 }
color: "#efefef"radius: 5border {
color: "darkgray"width: 1 }
}
Column {
id: controlColumnanchors {
left: parent.left
top: parent.top
margins: 10 }
spacing: 5Row {
spacing: 5Text {
id: fieldTextanchors.verticalCenter: parent.verticalCenter
text: "POP2000 >" }
TextField {
id: populationTextanchors.verticalCenter: parent.verticalCenter
width: 100text: "1100000"selectByMouse: truevalidator: IntValidator{}
}
}
Button {
anchors.horizontalCenter: parent.horizontalCenter
text: "Query in extent"onClicked: {
if (!citiesTable || !countiesTable || !statesTable)
return;
selectedFeaturesOverlay.graphics.clear();
// create the parametersconst queryParams = ArcGISRuntimeEnvironment.createObject("QueryParameters",
{
whereClause: fieldText.text + populationText.text,
geometry: mapView.currentViewpointExtent.extent
});
// query the feature tables citiesTable.queryFeatures(queryParams);
countiesTable.queryFeatures(queryParams);
statesTable.queryFeatures(queryParams);
}
}
}
SimpleMarkerSymbol {
id: citySymbolcolor: "red"size: 16style: Enums.SimpleMarkerSymbolStyleCircle
}
SimpleFillSymbol {
id: countyFillSymbolstyle: Enums.SimpleFillSymbolStyleDiagonalCross
color: "cyan"SimpleLineSymbol {
style: Enums.SimpleLineSymbolStyleDash
color: "cyan"width: 2 }
}
SimpleFillSymbol {
id: stateFillSymbolcolor: "transparent"SimpleLineSymbol {
id: stateLineSymbolcolor: "darkcyan"width: 6 }
}
}