ArcGIS 软件体系

ArcGIS 软件体系 • ArcGIS Desktop：一个专业GIS 应用的完整套件 • ArcGIS Engine：开发GIS 应用的嵌入式开发组件 • 服务器GIS：ArcSDE，ArcIMS和ArcGIS Server • 移动GIS：ArcPad 桌面GIS（ArcGIS Desktop），嵌入式GIS（ArcGIS Engine）以及服务器GIS （ArcGIS Server）都是基于一套共同的GIS 组件实现的，这些组件被称为ArcObjects。

Introducing COM • COM: 组件对象模型Component Object Model • 使用COM类Working with COM classes • 接口Interfaces • COM is a standard for creating classes • Classes can be reused between applications • Independent of programming language • All ArcObjects are COM classes

垃圾车 RaceCar 燃料 IDrive Fuel IDrive 加速 Accelerate 刹车 Brake IGarbage 倾倒 IRace 圈速度拾起停靠站 COM classes have interfaces • 对象拥有一个或多个接口 • 接口是定义了一组方法和属性的逻辑关系 • 与对象的通信是通过接口来进行的

GarbageTruck Fuel IDrive Accelerate Brake IGarbage Dump PickUp Working with ArcObjects COM classes • Instantiate COM classes with an interface • Dim <variable> As <some interface> • Interfaces group properties and methods Dim pGarbage As IDrive Set pGarbage = New GarbageTruck pGarbage.Fuel = "Full" pGarbage.Accelerate

IRadio ITape ICD More on interfaces … • 一个组合音响的例子 • 一个对象可以播放收音机、磁带、CD • 必须使用适当的接口 • 如果选择了播放磁带的接口，则不能收听收音机 Dim pBBox As ITape Set pBBox = New BoomBox pBBox.FM = True

Relationship symbols • 继承 • 组成 • 用来创建 • 对应关系 1：N • 联合鸟巢 CoClass Abstract * 羽毛小鸡 _____ * CoClass Class 2 蛋 Class 翅膀 Class

ArcMap objects • 类和他们相应的对象 Application MxDocument * Map * Layer FeatureLayer

Property Set (write) Property Get (read) Property and method symbols • Property • 哑铃形状的图标 • Method

Setting properties • Property Put: Most ArcObjects properties • Property holds a value or a copy of an object • Do not use Set keyword • Property Put by Reference: Some ArcObjects properties • Property holds a reference to an object • Must use the Set keyword • 如果引用对象发生了变化，对象的属性将同步受到影响 pLayer.Name = "Port Moresby" 'No Set keyword Set pLayer.FeatureClass = pMoresbyData'Must use Set!

Getting properties • Return a value • Name: String • Return an object reference • Document: IDocument • StatusBar: IStatusBar 返回一个值 Dim strName As String Dim pDoc As IDocument Dim pBar As IStatusBar strName = Application.Name MsgBox strName 返回一个引用 Set pDoc = Application.Document Set pBar = Application.StatusBar pBar.Message(0) pDoc.Title

Example: MxDocument > Map > layer • Get the FocusMap (active data frame) from MxDocument • MxDocument may have several Maps ( * ) • Get a layer from the the Map • Many types of layers ( ) MxDocument * Map Dim pMxDoc As IMxDocument Set pMxDoc = ThisDocument Dim pMap As IMap Set pMap = pMxDoc.FocusMap Dim pLayer As ILayer Set pLayer = pMap.Layer(1) 'Is pLayer a FeatureLayer? IfTypeOf pLayer Is IFeatureLayer Then MsgBox "Yes!, it’s a feature layer" End If * Layer FeatureLayer Others A

访问.shp文件的点要素属性 • IPointCollection 接口提供访问点属性的途径 • 可以通过“Polyline”类实例化，通过访问可以得到点的数量 • IPointCollection接口具有添加、移出、替换制定点的方法 • 访问点要素直接使用IPointCollection接口的point属性，point具有xy坐标值 • IPointCollection接口的ReplacePoints方法

ArcGIS 软件体系