Legend in Windows Forms Map (Maps)

A legend is a key used on a map that contains swatches of symbols with descriptions. A legend interprets what the map displays; it can be represented in various colors, shapes, or other identifiers based on data.

Visibility

Legends are visible only by setting the ShowLegend property to true in the ShapeFileLayer.

Legend position

Map legends can be positioned by setting the LegendPosition property in ShapeFileLayer. Also, the legend can be positioned based on the margin values for the x and y axes with the help of the PositionX and PositionY properties available in ShapeFileLayer. For positioning the legend based on margins corresponding to a map, LegendPosition must be set to “Default”.

Property Type Description
LegendPosition LegendPosition (enum) Gets or sets the standard position for legend
PositionX Double Gets or sets the margin value for x axis
PositionY Double Gets or sets the margin value for y axis.

Legend header

A header for the legend can be added by setting the Title property of string type.

Categories of Legend

Legends are categorized as the following two types:

  • Legends for layers
  • Legends for bubbles

These can be set by using the LegendType property.

Shapes for legend

Bubble type legends are always bubbles with varying sizes. The size of the bubbles is obtained from the SizeRatio of the BubbleSetting.

Layer shape type legends can be different shapes for the legend. The shapes can be set using the LegendIcon of the LegendIcon type.

Code sample:

partial class Form1
{

  private void InitializeComponent()
  {

            this.mapsControl1 = new Syncfusion.Windows.Forms.Maps.Maps();

            this.mapsControl1.Name = "mapsControl1";

            this.mapsControl1.Size = new System.Drawing.Size(880, 585); 

            this.Controls.Add(this.mapsControl1);  

            this.ClientSize = new System.Drawing.Size(880, 585);          

            this.Load += new System.EventHandler(this.Form1_Load);
}

            private Syncfusion.Windows.Forms.Maps.Maps mapsControl1;

}
public partial class Form1 : Form
{

        private void Form1_Load(object sender, EventArgs e)
        {

            this.mapsControl1.Dock = DockStyle.Fill;

            this.mapsControl1.Margin = new Padding(0, 0, 4, 0);

            this.mapsControl1.MapBackgroundBrush = new SolidBrush(Color.White);

            this.mapsControl1.MapItemsShape = Syncfusion.Windows.Forms.Maps.MapItemShapes.None;


            MapViewModel model = new MapViewModel();


            ShapeFileLayer shapeLayer = new ShapeFileLayer();

            shapeLayer.Uri = "world1.shp";

            shapeLayer.ItemSource = model.Countries;

            shapeLayer.ShapeIDPath = "NAME";

            shapeLayer.ShapeIDTableField = "NAME";

            shapeLayer.ShapeSetting.ShapeValuePath = "Population";

            shapeLayer.ShapeSetting.ShapeColorValuePath = "Population";

            shapeLayer.ShapeSetting.ShapeDisplayValuePath = "NAME";

            shapeLayer.ShapeSetting.TextForeground = "Black";

            shapeLayer.ShowMapItem = false;

            shapeLayer.ShowToolTip = true;

            shapeLayer.ShapeSetting.ShapeFill = "#E5E5E5";

            shapeLayer.ShapeSetting.ShapeStrokeThickness = 1.5;

            shapeLayer.ShapeSetting.ShapeStroke = "Black";

            shapeLayer.ShapeSetting.FillSetting.AutoFillColors = false;

            shapeLayer.LegendSetting = new LegendSettings()

            {

                ShowLegend = true, Size = new Size(15, 15), PositionX = 30, PositionY = 180

            };

            shapeLayer.ShapeSetting.FillSetting.ColorMappings = new System.Collections.ObjectModel.ObservableCollection<ColorMapping>();

            shapeLayer.ShapeSetting.FillSetting.ColorMappings.Add(new RangeColorMapping { From = 750000000, To = 1500000000, Color= Color.Coral });

            shapeLayer.ShapeSetting.FillSetting.ColorMappings.Add(new RangeColorMapping { From = 0, To = 750000000, Color =Color.Aqua });

            shapeLayer.ShapeSetting.FillSetting.ColorMappings.Add(new RangeColorMapping { From = 0, To = 0, Color = Color.CadetBlue });

             this.mapsControl1.Layers.Add(shapeLayer);

         }

}

The following screenshot illustrate a map displaying default legend