Add a point, line, and polygon

Learn how to display point, line, and polygon graphics in a map.

add a point line and polygon

You typically use graphics to display geographic data that is not connected to a database and that is not persisted, like highlighting a route between two locations, displaying a search buffer around a point, or tracking the location of a vehicle in real-time. Graphics are composed of a geometry, symbol, and attributes.

In this tutorial, you display points, lines, and polygons on a map as graphics.

Prerequisites

Before starting this tutorial:

  1. You need an ArcGIS Location Platform or ArcGIS Online account.

  2. Your system meets the system requirements.

Steps

Open the Xcode project

  1. To start the tutorial, complete the Display a map tutorial or download and unzip the solution.

  2. Open the .xcodeproj file in Xcode.

  3. If you downloaded the solution, get an access token and set the API key.

Add a graphics overlay

A graphics overlay is a container for graphics. It is used with a map view to display graphics on a map. You can add more than one graphics overlay to a map view. Graphics overlays are displayed on top of all the other layers.

  1. In Xcode, in the Project navigator, click ContentView.swift.

  2. Create a class called Model that adopts the ObservableObject protocol. Within that class, create a GraphicsOverlay as a default value. Initialize the property with an empty initializer and return it. You'll edit this method at a later step to add all of the graphics to display.

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    import SwiftUI
    import ArcGIS
    
    
    private class Model: ObservableObject {
        let graphicsOverlay: GraphicsOverlay = {
            let graphicsOverlay = GraphicsOverlay()
    
            return graphicsOverlay
    
        }()
    }
    
    
  3. Create a @StateObject of type Model called graphicsOverlayModel in the ContentView.

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    struct ContentView: View {
    
        @State private var map: Map = {
            let map = Map(basemapStyle: .arcGISTopographic)
            map.initialViewpoint = Viewpoint(latitude: 34.02700, longitude: -118.80500, scale: 72_000)
            return map
        }()
    
        @StateObject private var graphicsOverlayModel = Model()
    
    }
  4. In the body, update the map view initializer by adding the graphicsOverlays parameter. Pass in the graphicsOverlayModel's graphicOverlay property to add the graphics overlay created in the previous steps to the map view's list of graphics overlays.

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    struct ContentView: View {
    
        @State private var map: Map = {
            let map = Map(basemapStyle: .arcGISTopographic)
            map.initialViewpoint = Viewpoint(latitude: 34.02700, longitude: -118.80500, scale: 72_000)
            return map
        }()
    
        @StateObject private var graphicsOverlayModel = Model()
    
        var body: some View {
    
            MapView(map: map, graphicsOverlays: [graphicsOverlayModel.graphicsOverlay])
    
        }
    
    }

Add a point graphic

A point graphic is created using a point and a marker symbol. A point is defined with x and y coordinates, and a spatial reference. For latitude and longitude coordinates, the spatial reference is WGS84.

  1. Create a Point and a SimpleMarkerSymbol. To create the Point, provide longitude (x) and latitude (y) coordinates, and a SpatialReference. Use the SpatialReference.wgs84 convenience method. Create and style a SimpleMarkerSymbol.

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    private class Model: ObservableObject {
        let graphicsOverlay: GraphicsOverlay = {
            let graphicsOverlay = GraphicsOverlay()
    
            let point = Point(x: -118.80657, y: 34.00059, spatialReference: .wgs84)
            let pointSymbol = SimpleMarkerSymbol(style: .circle, color: .orange, size: 10.0)
            pointSymbol.outline = SimpleLineSymbol(style: .solid, color: .blue, width: 2.0)
    
            return graphicsOverlay
    
        }()
    }
    
    Expand
  2. Create a Graphic with the point and pointSymbol. Display the Graphic by adding it to the graphicsOverlay using the GraphicsOverlay.addGraphic() method.

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            let point = Point(x: -118.80657, y: 34.00059, spatialReference: .wgs84)
            let pointSymbol = SimpleMarkerSymbol(style: .circle, color: .orange, size: 10.0)
            pointSymbol.outline = SimpleLineSymbol(style: .solid, color: .blue, width: 2.0)
    
            let pointGraphic = Graphic(geometry: point, symbol: pointSymbol)
    
            graphicsOverlay.addGraphic(pointGraphic)
    
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  3. Press Command + R to run the app.

You should see a point graphic in Point Dume State Beach.

Add a line graphic

A line graphic is created using a polyline and a line symbol. A polyline is defined as a sequence of points.

  1. Create a Polyline and a SimpleLineSymbol. To create the Polyline, provide an array of Point objects. Create and style a SimpleLineSymbol.

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            graphicsOverlay.addGraphic(pointGraphic)
    
            let polyline = Polyline(
                points: [
                    Point(x: -118.82152, y: 34.01395, spatialReference: .wgs84),
                    Point(x: -118.81489, y: 34.00806, spatialReference: .wgs84),
                    Point(x: -118.80887, y: 34.00166, spatialReference: .wgs84)
                ]
            )
            let polylineSymbol = SimpleLineSymbol(style: .solid, color: .blue, width: 3.0)
    
    
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  2. Create a Graphic with the polyline and polylineSymbol. Display the Graphic by adding it to the graphicsOverlay using the GraphicsOverlay.addGraphic() method.

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            let polyline = Polyline(
                points: [
                    Point(x: -118.82152, y: 34.01395, spatialReference: .wgs84),
                    Point(x: -118.81489, y: 34.00806, spatialReference: .wgs84),
                    Point(x: -118.80887, y: 34.00166, spatialReference: .wgs84)
                ]
            )
            let polylineSymbol = SimpleLineSymbol(style: .solid, color: .blue, width: 3.0)
    
            let polylineGraphic = Graphic(geometry: polyline, symbol: polylineSymbol)
    
            graphicsOverlay.addGraphic(polylineGraphic)
    
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  3. Press Command + R to run the app.

You should see a point and line graphic along Westward Beach.

Add a polygon graphic

A polygon graphic is created using a polygon and a fill symbol. A polygon is defined as a sequence of points that describe a closed boundary.

  1. Create a Polygon and a SimpleFillSymbol. To create the Polygon, provide an array of Point objects. Create and style a SimpleFillSymbol.

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            graphicsOverlay.addGraphic(polylineGraphic)
    
            let polygon = Polygon(
                points: [
                    Point(x: -118.81898, y: 34.01375, spatialReference: .wgs84),
                    Point(x: -118.80679, y: 34.02158, spatialReference: .wgs84),
                    Point(x: -118.79143, y: 34.01638, spatialReference: .wgs84),
                    Point(x: -118.79596, y: 34.00856, spatialReference: .wgs84),
                    Point(x: -118.80855, y: 34.00350, spatialReference: .wgs84)
                ]
            )
            let polygonSymbol = SimpleFillSymbol(style: .solid, color: .orange, outline: SimpleLineSymbol(style: .solid, color: .blue, width: 2.0))
    
            return graphicsOverlay
    
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  2. Create a Graphic with the polygon and polygonSymbol. Display the Graphic by adding it to the graphicsOverlay's GraphicsOverlay.graphics collection.

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            graphicsOverlay.addGraphic(polylineGraphic)
    
            let polygon = Polygon(
                points: [
                    Point(x: -118.81898, y: 34.01375, spatialReference: .wgs84),
                    Point(x: -118.80679, y: 34.02158, spatialReference: .wgs84),
                    Point(x: -118.79143, y: 34.01638, spatialReference: .wgs84),
                    Point(x: -118.79596, y: 34.00856, spatialReference: .wgs84),
                    Point(x: -118.80855, y: 34.00350, spatialReference: .wgs84)
                ]
            )
            let polygonSymbol = SimpleFillSymbol(style: .solid, color: .orange, outline: SimpleLineSymbol(style: .solid, color: .blue, width: 2.0))
    
            let polygonGraphic = Graphic(geometry: polygon, symbol: polygonSymbol)
            graphicsOverlay.addGraphic(polygonGraphic)
    
            return graphicsOverlay
    
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  3. Press Command + R to run the app.

You should see a point, line, and polygon graphic around Mahou Riviera in the Santa Monica Mountains.

What's next?

Learn how to use additional API features, ArcGIS location services, and ArcGIS tools in these tutorials:

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