一、在ArcMap中的定位操作
已知若干点的经纬度坐标,要求在地图中进行定位:
1.通过Tool 》Add X Y data 定位点,注意选择地理坐标系下的wgs 1984坐标系;
2.定位后的点不能执行查询、分析等操作,需要重新export data;
3.导出的数据最好转换成投影坐标,以便于计算。可首先把已知投影坐标的图层加载到地图中,然后加入第二步产生的点图层,然后将点图层export data,注意坐标系统选择“the data frame”
二、在ArcObject开发时定位的代码示例
2.1 代码参考1
private void axMapControl1_OnMouseDown(object sender, IMapControlEvents2_OnMouseDownEvent e)
{ if (i >= )//测试目的
return;
i++; ITextElement te = createTextElement(e.mapX,e.mapY,"魁x");
axMapControl1.ActiveView.GraphicsContainer.AddElement(te as IElement, );
axMapControl1.Refresh(esriViewDrawPhase.esriViewGraphics, null, null); }
int i; public IBalloonCallout createBalloonCallout(double x, double y)
{
IRgbColor rgb = new RgbColorClass();
{
rgb.Red = ;
rgb.Green = ;
rgb.Blue = ; }
ISimpleFillSymbol sfs = new SimpleFillSymbolClass();
{
sfs.Color = rgb;
sfs.Style = esriSimpleFillStyle.esriSFSSolid;
} IPoint p = new PointClass();
{
p.PutCoords(x, y);
} IBalloonCallout bc = new BalloonCalloutClass();
{
bc.Style = esriBalloonCalloutStyle.esriBCSRoundedRectangle;
//
bc.Symbol = sfs;
//
bc.LeaderTolerance = ;
// bc.AnchorPoint = p;
} return bc;
} public ITextElement createTextElement(double x, double y, string text)
{
IBalloonCallout bc = createBalloonCallout(x, y); IRgbColor rgb = new RgbColorClass();
{
//rgb.Red = 255;
rgb.Green = ;
}
ITextSymbol ts = new TextSymbolClass();
{
ts.Color = rgb;
} IFormattedTextSymbol fts = ts as IFormattedTextSymbol;
{
fts.Background = bc as ITextBackground;
}
//fts.Size = 8;
ts.Size = ; IPoint point = new PointClass();
{
double width = axMapControl1.Extent.Width / ;
double height = axMapControl1.Extent.Height / ;
point.PutCoords(x + width, y + height);
} ITextElement te = new TextElementClass();
//IMarkerElement me = new MarkerElementClass();
{
te.Symbol = ts;
//ts.Text = text;
te.Text = text;
} IElement e = te as IElement;
{
e.Geometry = point;
}
return te; }
}
2.2 地图中添加label以标注地图
有多种方法:
1.使用TextElement
2.使用Label属性或与lyr文件或mxd文件结合进行标注
3.使用AnnotateLayerPropertiesCollection对象进行复杂标注
其中,第二种方法的代码为:
private void AddLabel2Map(string strField)
{
IGeoFeatureLayer pGeoFeatureLayer;
ILineLabelPosition pLineLabelPosition;
ILabelEngineLayerProperties pLabelEngineLayerProperties;
IAnnotateLayerProperties pAnnotateLayerProperties; pGeoFeatureLayer = (IGeoFeatureLayer)pMapControl.get_Layer();
pGeoFeatureLayer.AnnotationProperties.Clear(); pLineLabelPosition = new LineLabelPositionClass();
pLineLabelPosition.Above = false;
pLineLabelPosition.AtEnd = false;
pLineLabelPosition.Below = false;
pLineLabelPosition.Horizontal = false;
pLineLabelPosition.InLine = true;
pLineLabelPosition.OnTop = true;
pLineLabelPosition.Parallel = true;
pLineLabelPosition.ProduceCurvedLabels = true; pLabelEngineLayerProperties = new LabelEngineLayerPropertiesClass();
pLabelEngineLayerProperties.Symbol = new TextSymbolClass();
pLabelEngineLayerProperties.IsExpressionSimple = true;
pLabelEngineLayerProperties.Expression = "[" + strField + "]";//需要中括号
pLabelEngineLayerProperties.BasicOverposterLayerProperties.LineLabelPosition = pLineLabelPosition; pAnnotateLayerProperties = (IAnnotateLayerProperties)pLabelEngineLayerProperties;
pAnnotateLayerProperties.DisplayAnnotation = true;
pAnnotateLayerProperties.FeatureLayer = pGeoFeatureLayer; pAnnotateLayerProperties.LabelWhichFeatures = esriLabelWhichFeatures.esriAllFeatures;
pAnnotateLayerProperties.WhereClause = ""; pGeoFeatureLayer.AnnotationProperties.Add(pAnnotateLayerProperties);
pGeoFeatureLayer.DisplayAnnotation = true;
pMapControl.ActiveView.PartialRefresh(esriViewDrawPhase.esriViewGraphics, null, null);
}
这种方法的一个简化是,在ArcMap中事先设定好图层标记的属性,保存为mxd或lyr文件,程序中只使用
pGeoFeatureLayer.DisplayAnnotation和pGeoFeatureLayer.DisplayField设定显示的字段以及是否显示。
在ArcMap中设定的一些细节为:
1.设定标记是否重复、是否每个图元一个标记、或每个图元的每一部分都有一个标记,如图:
2.如何设定label只保留两位小数,如图:
还可以设置其他更为丰富的格式。
参考文章
1. 风过 无痕.arcEngine经典代码-添加气泡提示框(标注,文本,). 2008-8.
2. 丛晓男. 在地图中添加label以标注地图. 2010-6.