Use a symbol style to display a graphic on a graphics overlay.
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
- Create a
GraphicsOverlay
and add it to theMapView
. - Create a
Symbol
such asSimpleMarkerSymbol
,SimpleLineSymbol
orSimpleFillSymbol
. - Create a
Graphic
, specifying aGeometry
and aSymbol
. - Add the
Graphic
to theGraphicsOverlay
.
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
// Copyright 2022 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 Colors = System.Drawing.Color;
using PointCollection = Esri.ArcGISRuntime.Geometry.PointCollection;
namespace ArcGIS.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 : ContentPage
{
// Create the graphics overlay.
private readonly GraphicsOverlay _overlay = new GraphicsOverlay();
public AddGraphicsWithSymbols()
{
InitializeComponent();
// Create the UI, setup the control references and execute initialization.
Initialize();
}
private void Initialize()
{
// Create the map.
Map myMap = new Map(BasemapStyle.ArcGISOceans);
myMap.InitialViewpoint = new Viewpoint(56.075844, -2.681572, 13);
// 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, Colors.Red, 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, Colors.Purple, 4);
// Create a new point collection for polyline.
PointCollection points = new 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, Colors.Green, 1);
// Create a green mesh simple fill symbol.
SimpleFillSymbol fillSymbol = new SimpleFillSymbol(SimpleFillSymbolStyle.DiagonalCross, Colors.Green, outlineSymbol);
// Create a new point collection for polygon.
PointCollection points = new 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", Colors.Blue, 10,
Esri.ArcGISRuntime.Symbology.HorizontalAlignment.Left, Esri.ArcGISRuntime.Symbology.VerticalAlignment.Bottom);
TextSymbol craigleithTextSymbol = new TextSymbol("Craigleith", Colors.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));
}
}
}