ArcGIS二次开发基础教程(07)：简单符号及图层渲染

简单渲染

0. 点渲染

IGeoFeatureLayer GetLayerByName(string name){ILayer layer = null;for(int i=0;i<axMapConTrol1.LayerCount;i++){layer = axMapControl1.get_Layer(i);if(layer.Name.Equals(name))return layer as IGeoFeatureLayer;//这里转换为IGeoFeatureLayer是为了方便添加渲染器}return null;}//获取图层IGeoFeatureLayer geoFeatureLayer = GetLayerByName("图层名称");//创建简单渲染器ISimpleRenderer renderer = new SimpleRendererClass();//创建并设置形状的样式、颜色和大小ISimleMarkerSymbol simpleMarkerSymbol = new SimpleMarkerSymbolClass();IRGBColor color = new RGBClass();color.RGB = 251;simpleMarkerSymbol.Color = color;simpleMarkerSymbol.Style = esriSimleMarkerStyle.esriSMSX;simpleMarkerSymbol.Size = 10;renderer.Symbol = simpleMarkerSymbol as ISymbol;//设置图层渲染器geoFeatureLayer.Renderer = renderer;axMapControl1.Refresh();axTOCControl1.Update();

1. 线渲染

//线渲染和点渲染类似IGeoFeatueLayer geoFeatureLayer = GetLayerByName("图层名称");ISimpleRenderer renderer = new SimpleRendererClass();ISimpleLineSymbol simpleLineSymbol = new SimpleLineSymbolClass();IRGBColor color = new RGBColorClass();color.RGB = 251;simpleLineSymbol.Style = esriSimpleLineStyle.esriSLSDot;simpleLineSymbol.Color = color;simpleLineSymbol.Width = 2;renderer.Symbol = simpleLineSymbol as ISymbol;geoFeatureLayer.Renderer = renderer;axMapControl1.Refresh();axTOCControl1.Update();

2. 面渲染

IGeoFeatureLayer geoFeatureLayer = GeLayerByName("图层名称");ISimpleRenderer renderer = new SimpleRendererClass();//面相当于外轮廓线框加内部填充ISimpleFillSymbol simpleFillSymbol = new SimpleFillSymbolClass();//外轮廓线ISimpleLineSymbol simpleLineSymbol = new SimpleLineSymbolClass();IRGBColor color1 = new RGBColorClass();color.RGB = 251;//外轮廓线样式simpleLineSymbol.Style = esriSimpleLineStyle.esriSLSDot;simpleLineSymbol.Color = color;simpleLineSymbol.Width = 2;simpleFillSymbol.Color = color;//此处线颜色和内部填充颜色一致，也可不一致//内部填充样式simpleFillSymbol.Style = esriSimpleFillStyle.esriSFSVertical;simpleFillSymbol.Outline = simpleLineSymbol;renderer.Symbol = simpleFillSymbol as ISymbol;geoFeatureLayer.Renderer = renderer;axMapControl1.Refresh();axTOControl.Update();

唯一值渲染

//为图层要素类的某个字段所有不同要素属性值一个特定的颜色，区分不同。//随机获取颜色值 参数i是随机数种子 防止颜色相同IColor GetRandomColor(int i){Random ran = new Random(i);IRGBColor color = new RGBColorClass();color.Red = ran.Next(256);color.Green = ran.Next(256);color.Blue = ran.Next(256);return color;}void 唯一值渲染(){//创建一个唯一值渲染器IUniqueValueRendere uniqueValueRenderer = new UniqueValueRendererClass();//用来渲染的字段数 最多三个 这里仅设置一个uniqueValueRenderer.FieldCount = 1;uniqueValueRenderer.set_Field(0,"用来渲染的字段名");//获取图层IFeaturelayer featureLayer = GetLayerByName("图层名") as IFeatureLayer;//无条件查询获得所有要素的起始光标IFeatureCursor featureCursor = featurelayer.FeatureClass.Search(null,true);IFeature feature = featureCursor.Next();ISimpleFillSymbol simpleFillSymbol = null;//遍历所有要素为唯一值渲染器添加值while(feature!=null){int i = feature.get_value(0);string value = feature.get_Value(feature.Fields.FindField("用来渲染的字段名"));//渲染符号simpleFillSymbol = new SimpleFillSymbolClass();simpleFilleSymbol.Style = esriSimpleFillStyle.esriSFSSoild;simpleFillSymbol.Color = GetRandomColor(i);uniqueValueRenderer.AddValue(value,"用来渲染的字段名",simpleFillSymbol as iSymbol);}//设置图层的渲染器为唯一值渲染器IGeoFeatureLayer geoFeatureLayer = featureLayer as IGeoFeatureLayer;geoFeatureLayer.Renderer = uniqueValueRenderer as IFeatureRenderer;axMapControl1.Refresh();axTOCControl1.Update();}

分等级渲染

//将图层要素类的某个字段的属性值按给定数量的等级划分，用渐变颜色表示不同等级。//获得渐变颜色带IAlgorithmicColorRamp CreateAlgorithmicRamp(int count){//创建渐变颜色带IAlgorithmicColorRamp colorRamp = new AlgorithmicColorRampClass();colorRamp.size = count;//颜色数目//起始颜色对象IRGBColor fromColor = new RGBColorClass();fromColor.Red = 196;fromColor.Green = 10;fromColor.Blue = 10;//终止颜色对象IRGBColor toColor = new RGBColorClass();toColor.Red = 255;toColor.Green = 235;toColor.Blue = 214;colorRamp.ToColor = toColor;colorRamp.FromColor = fromColor;//梯度类型colorRamp.Algorithmic = esriColorRampAlgorithmic.esriCIELabAlgorithmic;bool ptrue = true;colorRamp.Create(out pture);return colorRamp;}void 分等级渲染(){int count = 10;//分级数量//该变量用于控制从表格中生成的直方图类型ITableHistogram tableHistogram = new BasicTableHistogramClass()IGeoFearureLayer geoFeatureLayer = GetLayerByName("欲渲染的图层名称");//将图层属性转换为表格ITable table = ((ILayer)geoFeatureLayer) as ITable;tableHistogram.Table = table;tableHistogram.Field = "用来渲染的字段名";//该变量用于从不同数据源中生成的直方图IBasicHistogram basicHitogram = tableHistogram as IBasicHistogram;//先统计每个值出现的次数，结果赋予valus，frequencesobject values;object frequences;basicHistogram.GetHistogram(out values, out frequences);//IClassifyGEN接口实现了很多分类接口，这里使用分类数分类方法IClassifyGEN classifyGEN = new QuantileClass();classifyGEN.Classify(values,frequens,ref count);//获取分类节点数据double[] classes = classifyGEN.Breaks as double[];//定义分级渲染器并设置相关属性IClassBreaksRenderer classBreaksRenderer = new ClassBreaksRendererClass();classBreaksRenderer.BreakCount = classes.Count;classBreaksRenderer.Field = "用来渲染的字段名";//升序显示classBreaksRenderer.SortClassesAscending = true;//提供渐变色带IAlgorithmicColorRamp rampColor = CreateAlgorithmicRamp(count);IEnumColor enumColor = rampCOlor.COlors;for(int i=0；i<classes.Count;i++){//设置渐变符号为填充，颜色由创建好的颜色带提供ISimpleFillSymbol simpleFillSymbol = new SimpleFillSymbolClass();simpleFillSymbol.COlor = enumColor.Next();simpleFillSymbol.Style = esriSimpleFillStyle.esriSFSSolid;//设置节点和符号classBreaksRenderer.set_Break(i,classes[i]);classBreaksRenderer.set_Symbol(i,simpleFillSymbol as ISymbol);}if(geoFeatureLayer!=null){//设置渲染器geoFeatureLayer.Renderer = classBreaksRenderer as IFeatrueRenderer;}axMapControl1.Refresh();axTOCControl1.Update();}

唯一值和分等级是最常用的图层渲染法，当然还有很多不同的渲染法，如符号大小渲染法，单一值渲染法，大同小异不一一介绍。

历届GIS应用技能大赛开发题答案点这里，尚在不定期更新中