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
GeometryEngineto check the relationship between the geometries, e.g.contains,disjoint,intersects, etc. If the method returnstrue, 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
// [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: rootRectangle
clip: true
width: 800
height: 600
MapView {
id: mapView
anchors.fill: parent
Component.onCompleted: {
// Set the focus on MapView to initially enable keyboard navigation
forceActiveFocus();
}
SelectionProperties {
color: "yellow"
}
Map {
Basemap {
initStyle: Enums.BasemapStyleArcGISTopographic
}
}
// Add a GraphicsOverlay
GraphicsOverlay {
id: graphicsOverlay
// Add Polygon Graphic
Graphic {
id: polygonGraphic
SimpleFillSymbol {
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 Graphic
Graphic {
id: polylineGraphic
SimpleLineSymbol {
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 Graphic
Graphic {
id: pointGraphic
SimpleMarkerSymbol {
color: "blue"
style: Enums.SimpleMarkerSymbolStyleCircle
size: 10
}
Point {
id: pointGeometry
x: -4487263.495911
y: 3699176.480377
SpatialReference {wkid: 3857}
Component.onCompleted: mapView.setViewpointCenterAndScale(pointGeometry, 200000000)
}
}
}
// connect to mouse click signal
onMouseClicked: mouse => {
mapView.identifyGraphicsOverlay(graphicsOverlay, mouse.x, mouse.y, 1 /*tolerance*/, false /*returnPopupsOnly*/);
}
// connect to identify signal
onIdentifyGraphicsOverlayStatusChanged: {
if (identifyGraphicsOverlayStatus !== Enums.TaskStatusCompleted)
return;
const identifiedGraphics = identifyGraphicsOverlayResult.graphics;
if (identifiedGraphics.length < 1)
return;
// get the first identified graphic
const graphic = identifiedGraphics[0];
// select the graphic
graphicsOverlay.clearSelection();
graphic.selected = true;
// get the geometry
const 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 itself
if (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 relaionships
function getSpatialRelationships(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: 0.85
radius: 5
color: "#e2e2e2"
border {
color: "darkgray"
width: 1
}
}
Column {
id: relationshipColumn
anchors {
left: parent.left
top: parent.top
margins: 15
}
spacing: 5
Text {
text: "Relationships:"
font {
pixelSize: 16
bold: true
family: "helvetica"
}
}
Text {
id: pointText
visible: text.length > 0
font.family: "helvetica"
}
Text {
id: lineText
visible: text.length > 0
font.family: "helvetica"
}
Text {
id: polygonText
visible: text.length > 0
font.family: "helvetica"
}
}
}