Add graphics with symbols

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Use a symbol style to display a graphic on a graphics overlay.

Image of Add graphics with symbols

Use case

Allows you to customize a graphic by assigning a unique symbol. For example, you may wish to display individual graphics for different landmarks across a region, and to style each one with a unique symbol.

How to use the sample

Observe the graphics on the map.

How it works

  1. Create a GraphicsOverlay and add it to the MapView.
  2. Create a Symbol such as SimpleMarkerSymbol, SimpleLineSymbol or SimpleFillSymbol.
  3. Create a Graphic, specifying a Geometry and a Symbol.
  4. Add the Graphic to the GraphicsOverlay.

Relevant API

  • Geometry
  • Graphic
  • GraphicsOverlay
  • SimpleFillSymbol
  • SimpleLineSymbol
  • SimpleMarkerSymbol

Additional information

To set a symbol style across a number of graphics (e.g. showing trees as graphics sharing a symbol in a park), see the "Add graphics with renderer" sample.

Tags

display, fill, graphics, line, marker, overlay, point, symbol

Sample Code

AddGraphicsWithSymbols.xaml.csAddGraphicsWithSymbols.xaml.csAddGraphicsWithSymbols.xaml
Use dark colors for code blocksCopy
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// 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.

using Esri.ArcGISRuntime.Geometry;
using Esri.ArcGISRuntime.Mapping;
using Esri.ArcGISRuntime.Symbology;
using Esri.ArcGISRuntime.UI;
using System.Drawing;

namespace ArcGIS.WPF.Samples.AddGraphicsWithSymbols
{
    [ArcGIS.Samples.Shared.Attributes.Sample(
        name: "Add graphics with symbols",
        category: "GraphicsOverlay",
        description: "Use a symbol style to display a graphic on a graphics overlay.",
        instructions: "Observe the graphics on the map.",
        tags: new[] { "display", "fill", "graphics", "line", "marker", "overlay", "point", "symbol" })]
    public partial class AddGraphicsWithSymbols
    {
        // Create the graphics overlay.
        private readonly GraphicsOverlay _overlay = new GraphicsOverlay();

        public AddGraphicsWithSymbols()
        {
            InitializeComponent();

            Initialize();
        }

        private void Initialize()
        {
            // Create the map.
            Map myMap = new Map(BasemapStyle.ArcGISOceans);
            myMap.InitialViewpoint = new Viewpoint(56.075844, -2.681572, 14);

            // Add the map to the map view.
            MyMapView.Map = myMap;

            // Add the graphics overlay to the map view.
            MyMapView.GraphicsOverlays.Add(_overlay);

            // Call functions to create the graphics.
            CreatePoints();
            CreatePolygon();
            CreatePolyline();
            CreateText();

            // Update the extent to encompass all of the symbols.
            SetExtent();
        }

        private void CreatePoints()
        {
            // Create a red circle simple marker symbol.
            SimpleMarkerSymbol redCircleSymbol = new SimpleMarkerSymbol(SimpleMarkerSymbolStyle.Circle, Color.FromArgb(0xFF, 0xFF, 0x00, 0x00), 10);

            // Create graphics and add them to graphics overlay.
            Graphic graphic = new Graphic(new MapPoint(-2.72, 56.065, SpatialReferences.Wgs84), redCircleSymbol);
            _overlay.Graphics.Add(graphic);

            graphic = new Graphic(new MapPoint(-2.69, 56.065, SpatialReferences.Wgs84), redCircleSymbol);
            _overlay.Graphics.Add(graphic);

            graphic = new Graphic(new MapPoint(-2.66, 56.065, SpatialReferences.Wgs84), redCircleSymbol);
            _overlay.Graphics.Add(graphic);

            graphic = new Graphic(new MapPoint(-2.63, 56.065, SpatialReferences.Wgs84), redCircleSymbol);
            _overlay.Graphics.Add(graphic);
        }

        private void CreatePolyline()
        {
            // Create a purple simple line symbol.
            SimpleLineSymbol lineSymbol = new SimpleLineSymbol(SimpleLineSymbolStyle.Dash, Color.FromArgb(0xFF, 0x80, 0x00, 0x80), 4);

            // Create a new point collection for polyline.
            Esri.ArcGISRuntime.Geometry.PointCollection points = new Esri.ArcGISRuntime.Geometry.PointCollection(SpatialReferences.Wgs84)
            {
                // Create and add points to the point collection.
                new MapPoint(-2.715, 56.061),
                new MapPoint(-2.6438, 56.079),
                new MapPoint(-2.638, 56.079),
                new MapPoint(-2.636, 56.078),
                new MapPoint(-2.636, 56.077),
                new MapPoint(-2.637, 56.076),
                new MapPoint(-2.715, 56.061)
            };

            // Create the polyline from the point collection.
            Polyline polyline = new Polyline(points);

            // Create the graphic with polyline and symbol.
            Graphic graphic = new Graphic(polyline, lineSymbol);

            // Add graphic to the graphics overlay.
            _overlay.Graphics.Add(graphic);
        }

        private void CreatePolygon()
        {
            // Create a green simple line symbol.
            SimpleLineSymbol outlineSymbol = new SimpleLineSymbol(SimpleLineSymbolStyle.Dash, Color.FromArgb(0xFF, 0x00, 0x50, 0x00), 1);

            // Create a green mesh simple fill symbol.
            SimpleFillSymbol fillSymbol = new SimpleFillSymbol(SimpleFillSymbolStyle.DiagonalCross, Color.FromArgb(0xFF, 0x00, 0x50, 0x00), outlineSymbol);

            // Create a new point collection for polygon.
            Esri.ArcGISRuntime.Geometry.PointCollection points = new Esri.ArcGISRuntime.Geometry.PointCollection(SpatialReferences.Wgs84)
            {
                // Create and add points to the point collection.
                new MapPoint(-2.6425, 56.0784),
                new MapPoint(-2.6430, 56.0763),
                new MapPoint(-2.6410, 56.0759),
                new MapPoint(-2.6380, 56.0765),
                new MapPoint(-2.6380, 56.0784),
                new MapPoint(-2.6410, 56.0786)
            };

            // Create the polyline from the point collection.
            Polygon polygon = new Polygon(points);

            // Create the graphic with polyline and symbol.
            Graphic graphic = new Graphic(polygon, fillSymbol);

            // Add graphic to the graphics overlay.
            _overlay.Graphics.Add(graphic);
        }

        private void CreateText()
        {
            // Create two text symbols.
            TextSymbol bassRockTextSymbol = new TextSymbol("Black Rock", Color.Blue, 10,
                Esri.ArcGISRuntime.Symbology.HorizontalAlignment.Left, Esri.ArcGISRuntime.Symbology.VerticalAlignment.Bottom);

            TextSymbol craigleithTextSymbol = new TextSymbol("Craigleith", Color.Blue, 10,
                Esri.ArcGISRuntime.Symbology.HorizontalAlignment.Right, Esri.ArcGISRuntime.Symbology.VerticalAlignment.Top);

            // Create two points.
            MapPoint bassPoint = new MapPoint(-2.64, 56.079, SpatialReferences.Wgs84);
            MapPoint craigleithPoint = new MapPoint(-2.72, 56.076, SpatialReferences.Wgs84);

            // Create two graphics from the points and symbols.
            Graphic bassRockGraphic = new Graphic(bassPoint, bassRockTextSymbol);
            Graphic craigleithGraphic = new Graphic(craigleithPoint, craigleithTextSymbol);

            // Add graphics to the graphics overlay.
            _overlay.Graphics.Add(bassRockGraphic);
            _overlay.Graphics.Add(craigleithGraphic);
        }

        private void SetExtent()
        {
            // Get all of the graphics contained in the graphics overlay.
            GraphicCollection myGraphicCollection = _overlay.Graphics;

            // Create a new envelope builder using the same spatial reference as the graphics.
            EnvelopeBuilder myEnvelopeBuilder = new EnvelopeBuilder(SpatialReferences.Wgs84);

            // Loop through each graphic in the graphic collection.
            foreach (Graphic oneGraphic in myGraphicCollection)
            {
                // Union the extent of each graphic in the envelope builder.
                myEnvelopeBuilder.UnionOf(oneGraphic.Geometry.Extent);
            }

            // Expand the envelope builder by 30%.
            myEnvelopeBuilder.Expand(1.3);

            // Adjust the viewable area of the map to encompass all of the graphics in the
            // graphics overlay plus an extra 30% margin for better viewing.
            MyMapView.SetViewpointAsync(new Viewpoint(myEnvelopeBuilder.Extent));
        }
    }
}

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