【转】ArcGIS API for Silverlight/WPF 2.1学习笔记(二)

 

五、Graphics layer

1、新增Graphics layer

Graphics layer用于显示用户自定义绘制的点、线、面图形。使用时确保xaml文件中Graphics layer定义在其它图层的下面,以确保它能显示在其它图层的上面。

<esri:Map x:Name="MyMap" Extent=", , , " >

       <esri:Map.Layers>                      

<esri:ArcGISTiledMapServiceLayerID="."Url="http://../rest/./MapServer"/>

              <esri:GraphicsLayer ID=”.” />

       </esri:Map.Layers>

</esri:Map>

 

2、管理Graphics features

Graphics layer上创建Graphics的步骤一般如下:

1)获取Graphics layer

2)创建或获取Graphic

3)设置GraphicGeometry

4)应用GraphicSymbol

5)将Graphic添加到Graphics layers

代码如下:

GraphicsLayer graphicsLayer = MyMap.Layers["MyGraphicsLayer"] as GraphicsLayer;

foreach (Graphic graphic in graphicsList)

{

    graphic.Symbol = MySymbol;

    graphicsLayer.Graphics.Add(graphic);

}

 

3、使用Draw surface

Draw surface用于获取GeometriesGeometries可添加到Graphics Layer或用作identifybuffer操作。

       使用Draw surface,你必须

1)设置绘图操作的Symbols

2)设置Draw surface的地图

3)执行逻辑以激活|解除surface

4)处理Geometries,以在surface上绘图

示例代码如下:

xaml文件:

<Grid x:Name="LayoutRoot" Background="White">

              <Grid.Resources>

                     <esriSymbols:SimpleFillSymbol x:Name="RedFillSymbol" Fill="#66FF0000" BorderBrush="Red" BorderThickness="2" />

              </Grid.Resources>

              <esri:Map …>

cs文件:

MyDrawObject = new Draw(MyMap)

{ LineSymbol =LayoutRoot.Resources["DrawLineSymbol"] as LineSymbol,

FillSymbol =LayoutRoot.Resources["DrawFillSymbol"] as FillSymbol };

MyDrawObject.DrawComplete += MyDrawObject_DrawComplete;

MyDrawObject.DrawMode = DrawMode.Polygon;

MyDrawObject.IsEnabled = true;

private void MyDrawObject_DrawComplete(object sender, ESRI.ArcGIS.Client.DrawEventArgs args)

{

    Graphic graphic = new Graphic() { Geometry = args.Geometry, Symbol = RedFillSymbol };

GraphicsLayer graphicsLayer = MyMap.Layers["MyGraphicsLayer"] as GraphicsLayer;

graphicsLayer.Graphics.Add(graphic);

}

 

4SymbolsRenderers

       Symbols定义了Graphic的非几何学方面的显示特性,如颜色、边框宽度、透明度等。

       Renderers定义了一个或多个应用于Graphics layerSymbols,指定哪些Graphics属性与哪个Symbol相符。

SymbolsGeometries类型:

Symbol

Geometry

描述

SimpleMarkerSymbol

Point

用简单形状来表现点

PictureMarkerSymbol

Point

images来表现点

SimpleLineSymbol

Polyline

用预定义的风格来表现线

CartographicLineSymbol

Polyline

用定制的风格来表现线

SimpleFillSymbol

Polygon

Silverlight Brush来填充多边形

PictureFillSymbol

Polygon

images填充多边形

 

 

通常,视觉定义在xaml文件中,行为逻辑定义在.cs文件中,让表现层和业务逻辑层分开,使得应用程序更容易开发、维护和扩展。

 

Symbol的使用:

1)添加命名空间:symbol类定义在ESRI.ArcGIS.Client.Symbols命名空间中(ESRI.ArcGIS.Client集)

xmlns:esriSymbols="clr-namespace:ESRI.ArcGIS.Client.Symbols;assembly=ESRI.ArcGIS.Client"

2xaml文件中定义Symbol

<Grid.Resources>

<esriSymbols:SimpleFillSymbol x:Name="MyRedFillSymbol" Fill="#66FF0000" BorderBrush="Red" BorderThickness="2" />

</Grid.Resources>

//Symbol运用于FeatureLayer

<esri:FeatureLayer ID="." Where="1=1" FeatureSymbol="{StaticResource MyRedFillSymbol}"

Url="http://./ArcGIS/rest/services/./MapServer/5" >

<esri:FeatureLayer.OutFields>

<sys:String>POP07_SQMI</sys:String>

       </esri:FeatureLayer.OutFields>

</esri:FeatureLayer>

3cs文件中动态生成

SimpleFillSymbol fillSymbol = new SimpleFillSymbol()

  {

     BorderBrush = new SolidColorBrush(Color.FromArgb(0, 255, 0, 0)),

     BorderThickness = 2,

     Fill = new SolidColorBrush(Color.FromArgb(alphaVal, redVal, greenVal, blueVal))

  };

//Symbol运用于GraphicsLayer的每一个graphic

GraphicsLayer graphicsLayer = MyMap.Layers["MyGraphicsLayer"] as GraphicsLayer;

foreach (Graphic graphic in graphicsLayer.Graphics)

graphic.Symbol = fillSymbol;

 

创建Unique Value Renderer

<Grid.Resources>

<esriSymbols:SimpleFillSymbol x:Name="a" Fill=""BorderBrush=""BorderThickness="" />

<esriSymbols:SimpleFillSymbol x:Name="b" Fill=""BorderBrush=""BorderThickness="" />

<esriSymbols:SimpleFillSymbol x:Name="c" Fill=""BorderBrush=""BorderThickness="" />

       <esri:UniqueValueRenderer x:Name="abcRenderer" Attribute="STATE_NAME" >

              <esri:UniqueValueRenderer.Infos>

                     <esri:UniqueValueInfo Value="California" Symbol="{StaticResource  a}" />

                     <esri:UniqueValueInfo Value="New York" Symbol="{StaticResource  b}" />

                     <esri:UniqueValueInfo Value="Kansas" Symbol="{StaticResource    c}" />

              </esri:UniqueValueRenderer.Infos>

       </esri:UniqueValueRenderer>

</Grid.Resources>

// FeatureLayer中,指定一个过滤,仅仅CaliforniaNew YorkKansas被绘制

//并且将其STATE_NAME字段的值显示在layerGraphics

<esri:FeatureLayer ID=""

Where="(STATE_NAME='California') OR (STATE_NAME='New York') OR (STATE_NAME = 'Kansas')"

Renderer="{StaticResource  abcRenderer}"

       Url="http://sampleserver1.arcgisonline.com/ArcGIS/rest/services/Demographics/ESRI_Census_USA/MapServer/5" >

       <esri:FeatureLayer.OutFields>

              <sys:String>STATE_NAME</sys:String>

       </esri:FeatureLayer.OutFields>

</esri:FeatureLayer>

 

创建Class Breaks Renderer:即将symbol应用于一组指定范围的graphics中。

<Grid.Resources>

<esriSymbols:SimpleFillSymbol x:Name="a" Fill="" BorderBrush=""BorderThickness="" />

<esriSymbols:SimpleFillSymbol x:Name="b" Fill="" BorderBrush=""BorderThickness="" />

<esriSymbols:SimpleFillSymbol x:Name="c" Fill="" BorderBrush=""BorderThickness="" />

       <esri:ClassBreaksRenderer x:Name="abcRenderer" Attribute="POP07_SQMI" >

              <esri:ClassBreaksRenderer.Classes>

                     <esri:ClassBreakInfo MinimumValue="0" MaximumValue="50" Symbol="{StaticResource  a}" />

                     <esri:ClassBreakInfo MinimumValue="51" MaximumValue="125" Symbol="{StaticResource  b}" />

                     <esri:ClassBreakInfo MinimumValue="125" MaximumValue="2000" Symbol="{StaticResource  c}" />

              </esri:ClassBreaksRenderer.Classes>

       </esri:ClassBreaksRenderer>

</Grid.Resources>

// FeatureLayer中,将rendererFeature layer联系起来,进行地图绘制

//并且将其POP07_SQMI字段的值显示在layerGraphics

<esri:FeatureLayer ID="" Where="1=1" Renderer="{StaticResource abcRenderer}"

Url="http://./ArcGIS/rest/services/./MapServer/5" >

       <esri:FeatureLayer.OutFields>

              <sys:String>POP07_SQMI</sys:String>

       </esri:FeatureLayer.OutFields>

</esri:FeatureLayer>

 

5、使用Clustering(聚类分组,用于render的数量很大时)

当点很多和密集时,使用Clustering将点分组,使得在cluster distance内的多个点用一个点代替。Clustering可用于GraphicsLayerFeature Layer

1)使用FlareClusterer

FlareClusterer可按如下方式添加到GraphicsLayerFeatureLayer中:

<esri:GraphicsLayer ID="MyGraphicsLayer">

   <esri:GraphicsLayer.Clusterer>

      <esri:FlareClusterer />

   </esri:GraphicsLayer.Clusterer>

</esri:GraphicsLayer>

效果如下图:

【原创】ArcGIS API for Silverlight/WPF 2.1学习笔记(二) - 清风明月 - 老钟的GIS小站

FlareClusterer的属性如下表:

FlareClusterer属性

描述

FlareBackground

填充的背景颜色(默认红色)

FlareForeground

边界和文字颜色(默认白色)

MaximumFlareCount

当鼠标移动到cluster时,各小点是否展开的最大数量界限

小于此值时,鼠标移上去会展开各小点;大于此值时,称为large clusters,其颜色和大小会根据点多少变化。(默认=10

Radius

cluster的半径,单位pixels(默认20

Gradient

LinearGradientBrush线性渐变刷用于large clusters

(默认:Default = LinearGradientBrush; MappingMode = RelativeToBoundingBox; GradientStop1: Offset = 0, Argb = 127,255,255,0, GradientStop2: Offset = 1, Argb = 127,255,0,0)

示例:修改FlareClusterer的默认属性

<Grid.Resources>

<LinearGradientBrush x:Name="aGradient" MappingMode="RelativeToBoundingBox" >

              <GradientStop Color="#990011FF" Offset="0"/>

              <GradientStop Color="#990055FF" Offset="0.25"/>

              <GradientStop Color="#990099FF" Offset="0.5"/>

              <GradientStop Color="#9900CCFF" Offset="0.75"/>

              <GradientStop Color="#9900FFFF" Offset="1"/>

    </LinearGradientBrush>

</Grid.Resources>

<esri:Map x:Name="MyMap">

    <esri:Map.Layers>

          <esri:GraphicsLayer ID="MyGraphicsLayer">

           <esri:GraphicsLayer.Clusterer>

                     <esri:FlareClusterer FlareBackground="Yellow" FlareForeground="#99000000"

              MaximumFlareCount="5" Radius="15" Gradient="{StaticResource aGradient}" />

           </esri:GraphicsLayer.Clusterer>

          </esri:GraphicsLayer>

    </esri:Map.Layers>

</esri:Map>

 

2)扩展GraphicsClusterer

为了定制cluster的外观,你可以创建一个继承自ESRI.ArcGIS.Client.GraphicsClusterer的类,并重写OnCreateGraphic()方法来定义cluster graphic。示例代码如下:

public class SumClusterer : GraphicsClusterer

{

    public SumClusterer()

    {

        MinimumColor = Colors.Red;

        MaximumColor = Colors.Yellow;

        SymbolScale = 1;

        base.Radius = 50;

    }

    public string AggregateColumn { get; set; }

    public double SymbolScale { get; set; }

    public Color MinimumColor { get; set; }

    public Color MaximumColor { get; set; }

    protected override Graphic OnCreateGraphic(GraphicCollection cluster, MapPoint point, int maxClusterCount)

    {

        if (cluster.Count == 1) return cluster[0];

        Graphic graphic = null;

        double sum = 0;

        foreach (Graphic g in cluster)

        {

            if (g.Attributes.ContainsKey(AggregateColumn))

            {try{sum += Convert.ToDouble(g.Attributes[AggregateColumn]); }}

        }

        double size = (sum + 450) / 30;

        size = (Math.Log(sum * SymbolScale / 10) * 10 + 20);

        if (size < 12) size = 12;

        graphic=new Graphic(){Symbol=new ClusterSymbol() {Size = size},Geometry= point};

        graphic.Attributes.Add("Count", sum);

        graphic.Attributes.Add("Size", size);

        graphic.Attributes.Add("Color", InterpolateColor(size - 12, 100));

        return graphic;

}

    private static Brush InterpolateColor(double value, double max)

    {

        value = (int)Math.Round(value * 255.0 / max);

        if (value > 255) value = 255;

        else if (value < 0) value = 0;

        return new SolidColorBrush(Color.FromArgb(127, 255, (byte)value, 0));

    }

}



posted @ 2013-09-06 18:04  长白山  阅读(382)  评论(0编辑  收藏  举报