一、技术原理

CityMaker中图层（featurelayer）符号化指的通过设置颜色或者透明度等样式来改变整个图层的样式，具体详见如图：

CityMaker几何体——符号化 - 图1

图层符号化有两种方法：
·创建图层的时候设置geometryrender；
·通过setGeometryRender设置geometryrender；

几何渲染器IGeometryRender分为简易几何渲染对象ISimpleGeometryRender和多专题的几何渲染器IValueMapGeometryRender

简易几何渲染一般是通过设置几何对象的样式来设置
多专题的几何渲染主要是用渲染方案来设置渲染的效果，渲染方案有两个渲染的规则，一个是范围规则，也就是可以设置在规定范围中显示某种渲染效果，另一个是唯一值渲染规则，也就是可以根据某一类型来实现渲染的效果

二、图层符号化

1. .NET

  1. private Hashtable fcMap = null; 
  2. //定义建筑图层        
  3. IFeatureLayer BuildingFl=null;
  4. //创建图层
  5. public void CreateFeaturelayer()
  6. {
  7.      //几何物体渲染风格
  8.      ISimpleGeometryRender geoRender = new SimpleGeometryRender();
  9.      IModelPointSymbol geoSymbol = new ModelPointSymbol();
  10.      geoSymbol.Color = 0xFFDDDD00;  //模型颜色
  11.      geoSymbol.EnableColor = true;  //需开启，否则颜色设置无效
  12.      geoRender.Symbol = geoSymbol;
  15.      IFeatureLayer featureLayer = rendercontrol.ObjectManager.CreateFeatureLayer(
  16.      fc, geoName, null, geoRender, __rootId);
  17. }
  20. //1、简易几何渲染，通过设置颜色，来渲染模型
  21. public void SimpleSymbol() {
  22.      ISimpleGeometryRender geoRender = new SimpleGeometryRender();
  23.      IModelPointSymbol geoSymbol = new ModelPointSymbol();
  24.      geoSymbol.Color = 0xFF000000;  //模型颜色
  25.      geoSymbol.EnableColor = true;  //需开启，否则颜色设置无效
  26.      geoRender.Symbol = geoSymbol;
  27.      BuildingFl.SetGeometryRender(geoRender);
  28. }
  31. //2、多专题的几何渲染器,通过设置范围来渲染不同范围的模型
  32. public void ValueSymbol() {
  33.      //几何渲染风格
  34.      IValueMapGeometryRender geoRender = new ValueMapGeometryRender();
  37.      IRangeRenderRule rangeRule = new RangeRenderRule();
  38.      rangeRule.LookUpField = "oid";
  39.      rangeRule.MaxValue = 60000;
  40.      rangeRule.MinValue = 0;
  41.      rangeRule.IncludeMin = false;
  44.      IModelPointSymbol geoSymbol = new ModelPointSymbol();
  45.      geoSymbol.Color = 0xFF7D7D00;  //模型颜色
  46.      geoSymbol.EnableColor = true;  //需开启，否则颜色设置无效
  49.      IGeometryRenderScheme grs = new GeometryRenderScheme();
  50.      grs.AddRule(rangeRule);
  51.      grs.Symbol = geoSymbol;
  52.      geoRender.AddScheme(grs);
  53.      BuildingFl.SetGeometryRender(geoRender);
  54. }

2. JavaScript

  1. //创建图层
  2. function createFeaturelayer(){
  3.     //初始化一个简易几何渲染
  4.     var geoRender=__g.new_SimpleGeometryRender;
  5.     //此处用的是模型图层为例，其他数据类型类似，只是渲染的几何风格不同
  6.     var modelPointSymbol = __g.new_ModelPointSymbol;
  7.     modelPointSymbol.color=0x64FFFFFF;
  8.     modelPointSymbol.enableColor = true;
  9.     geoRender.symbol=modelPointSymbol;
  12.     var fl = __g.objectManager.createFeatureLayer(fc, geoName, textRender, geoRender, __rootId);
  13. }
  16. //1、简易几何渲染，通过设置颜色，来渲染模型
  17. function changeSimpleSymbol(){
  18.     var geoRender=__g.new_SimpleGeometryRender;
  19.     var modelPointSymbol = __g.new_ModelPointSymbol;
  20.     modelPointSymbol.color=0xff097CEA;
  21.     modelPointSymbol.enableColor = true;
  22.     geoRender.symbol=modelPointSymbol;
  23.     buildingFl.setGeometryRender(geoRender);
  24. }
  27. //2、多专题的几何渲染器,通过设置范围来渲染不同范围的模型
  28. function changeValueSymbol(){
  29.     var geoRender = __g.new_ValueMapGeometryRender;       
  30.     var rangeRule = __g.new_RangeRenderRule;
  31.     rangeRule.lookUpField = "oid";
  32.     rangeRule.maxValue = 1290;
  33.     rangeRule.minValue = 0;
  38.     var geoSymbol = __g.new_ModelPointSymbol;
  39.     geoSymbol.color = 0xFFEAD60A;  
  40.     geoSymbol.enableColor = true;  //需开启，否则颜色设置无效
  43.     var grs = __g.new_GeometryRenderScheme;
  44.     grs.addRule(rangeRule);
  45.     grs.symbol = geoSymbol;
  46.     geoRender.addScheme(grs);
  49.     var rangeRule = __g.new_RangeRenderRule;
  50.     rangeRule.lookUpField = "oid";
  51.     rangeRule.maxValue = 3290;
  52.     rangeRule.minValue = 1290;
  55.     var geoSymbol = __g.new_ModelPointSymbol;
  56.     geoSymbol.color = 0xcc3103C1;  //模型颜色
  57.     geoSymbol.enableColor = true;  //需开启，否则颜色设置无效
  60.     var grs = __g.new_GeometryRenderScheme;
  61.     grs.addRule(rangeRule);
  62.     grs.symbol = geoSymbol;
  63.     geoRender.addScheme(grs);
  66.     buildingFl.setGeometryRender(geoRender);
  67. }

3. 注意

  1. 几何渲染风格的enableColor必须设置为true，否则颜色设置无效
  2. 简易几何渲染包含各种数据类型的图层设置，不仅是模型图层，也可以是点线面图层
  3. 专题渲染可以同时添加多个渲染规则