Determine spatial relationships between two geometries.
Use case
In case of a natural disaster, emergency services can represent the affected areas using polygons. By determining the spatial relationships between these and any other existing features such as populated areas, infrastructure, or natural resources, it is possible to quickly determine which of the existing features might be affected or is in further danger, helping to assess risk and define further action.
How to use the sample
Select one of the three graphics. The tree view will list the relationships the selected graphic has to the other graphic geometries.
How it works
Get the geometry from two different graphics. In this example the geometry of the selected graphic is compared to the geometry of each unselected graphic.
Use the methods in GeometryEngine to check the relationship between the geometries, e.g. contains, disjoint, intersects, etc. If the method returns true, the relationship exists.
Relevant API
Geometry
GeometryEngine
GeometryEngine.contains
GeometryEngine.crosses
GeometryEngine.disjoint
GeometryEngine.intersects
GeometryEngine.overlaps
GeometryEngine.touches
GeometryEngine.within
GeometryType
Graphic
Point
Polygon
Polyline
Tags
geometries, relationship, spatial analysis
Sample Code
SpatialRelationships.qml
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// [WriteFile Name=SpatialRelationships, Category=Geometry]// [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 Esri.ArcGISRuntime
Rectangle {
id: rootRectangleclip: truewidth: 800height: 600MapView {
id: mapViewanchors.fill: parentComponent.onCompleted: {
// Set the focus on MapView to initially enable keyboard navigation forceActiveFocus();
}
SelectionProperties {
color: "yellow" }
Map {
Basemap {
initStyle: Enums.BasemapStyleArcGISTopographic
}
}
// Add a GraphicsOverlayGraphicsOverlay {
id: graphicsOverlay// Add Polygon GraphicGraphic {
id: polygonGraphicSimpleFillSymbol {
SimpleLineSymbol {
color: "green"width: 2 }
style: Enums.SimpleFillSymbolStyleForwardDiagonal
color: "green" }
Component.onCompleted: {
const polyBuilder = ArcGISRuntimeEnvironment.createObject("PolygonBuilder", {spatialReference: Factory.SpatialReference.createWebMercator()});
polyBuilder.addPointXY(-5991501.677830, 5599295.131468);
polyBuilder.addPointXY(-6928550.398185, 2087936.739807);
polyBuilder.addPointXY(-3149463.800709, 1840803.011362);
polyBuilder.addPointXY(-1563689.043184, 3714900.452072);
polyBuilder.addPointXY(-3180355.516764, 5619889.608838);
polygonGraphic.geometry = polyBuilder.geometry;
}
}
// Add Polyline GraphicGraphic {
id: polylineGraphicSimpleLineSymbol {
style: Enums.SimpleLineSymbolStyleDash
color: "red"width: 4 }
Component.onCompleted: {
const polyBuilder = ArcGISRuntimeEnvironment.createObject("PolylineBuilder", {spatialReference: Factory.SpatialReference.createWebMercator()});
polyBuilder.addPointXY(-4354240.726880, -609939.795721);
polyBuilder.addPointXY(-3427489.245210, 2139422.933233);
polyBuilder.addPointXY(-2109442.693501, 4301843.057130);
polyBuilder.addPointXY(-1810822.771630, 7205664.366363);
polylineGraphic.geometry = polyBuilder.geometry;
}
}
// Add Point GraphicGraphic {
id: pointGraphicSimpleMarkerSymbol {
color: "blue"style: Enums.SimpleMarkerSymbolStyleCircle
size: 10 }
Point {
id: pointGeometryx: -4487263.495911y: 3699176.480377SpatialReference {wkid: 3857}
Component.onCompleted: mapView.setViewpointCenterAndScale(pointGeometry, 200000000)
}
}
}
// connect to mouse click signalonMouseClicked: mouse => {
mapView.identifyGraphicsOverlay(graphicsOverlay, mouse.x, mouse.y, 1/*tolerance*/, false/*returnPopupsOnly*/);
}
// connect to identify signalonIdentifyGraphicsOverlayStatusChanged: {
if (identifyGraphicsOverlayStatus !== Enums.TaskStatusCompleted)
return;
const identifiedGraphics = identifyGraphicsOverlayResult.graphics;
if (identifiedGraphics.length < 1)
return;
// get the first identified graphicconst graphic = identifiedGraphics[0];
// select the graphic graphicsOverlay.clearSelection();
graphic.selected = true;
// get the geometryconst selectedGeometry = graphic.geometry;
const selectedGeometryType = selectedGeometry.geometryType;
// reset the output text pointText.text = "";
lineText.text = "";
polygonText.text = "";
// populate the view with the spatial relationships the selected graphic has to the other graphics// ignore testing relationships between the geometry and itselfif (selectedGeometryType !== Enums.GeometryTypePoint) {
const pointRelationships = getSpatialRelationships(selectedGeometry, pointGraphic.geometry).toString();
pointText.text = "Point: %1".arg(pointRelationships);
}
if (selectedGeometryType !== Enums.GeometryTypePolyline) {
const polylineRelationships = getSpatialRelationships(selectedGeometry, polylineGraphic.geometry).toString();
lineText.text = "Polyline: %1".arg(polylineRelationships);
}
if (selectedGeometryType !== Enums.GeometryTypePolygon) {
const polygonRelationships = getSpatialRelationships(selectedGeometry, polygonGraphic.geometry).toString();
polygonText.text = "Polygon: %1".arg(polygonRelationships);
}
}
}
// function to return list of relaionshipsfunctiongetSpatialRelationships(geom1, geom2) {
const relationships = [];
if (GeometryEngine.crosses(geom1, geom2))
relationships.push("CROSSES");
if (GeometryEngine.contains(geom1, geom2))
relationships.push("CONTAINS");
if (GeometryEngine.disjoint(geom1, geom2))
relationships.push("DISJOINT");
if (GeometryEngine.intersects(geom1, geom2))
relationships.push("INTERSECTS");
if (GeometryEngine.overlaps(geom1, geom2))
relationships.push("OVERLAPS");
if (GeometryEngine.touches(geom1, geom2))
relationships.push("TOUCHES");
if (GeometryEngine.within(geom1, geom2))
relationships.push("WITHIN");
return relationships;
}
Rectangle {
anchors {
fill: relationshipColumn
margins: -10 }
opacity: 0.85radius: 5color: "#e2e2e2"border {
color: "darkgray"width: 1 }
}
Column {
id: relationshipColumnanchors {
left: parent.left
top: parent.top
margins: 15 }
spacing: 5Text {
text: "Relationships:"font {
pixelSize: 16bold: truefamily: "helvetica" }
}
Text {
id: pointTextvisible: text.length > 0font.family: "helvetica" }
Text {
id: lineTextvisible: text.length > 0font.family: "helvetica" }
Text {
id: polygonTextvisible: text.length > 0font.family: "helvetica" }
}
}