ArcEngine开发入门-4.ppt

栅格空间分析,AE栅格数据模型,RasterDataset,表示以某种特定格式存贮在磁盘文件、数据库或内存中的栅格数据集。可进行基本的copy、rename、delete等管理实现了IRasterDataset、IGeoDataset、IGeoDataset2等接口,RasterBand,表示栅格数据的一个波段通过RasterBand可访问颜色表、栅格直方图、统计量、RAT表等。,Raster,表示栅格数据的一种临时状态。对Raster的改变不会引起源数据的改变。可以用Raster表达各种栅格数据处理的输出结果。总是和一个或多个RasterBand相关联。可由RasterDataset创建得到CreateFullRaster：创建包含所有内容的RasterCreateDefaultRaster：只包含3个波段实现了IRasterProps接口访问栅格属性。实现了IGeoDataset、IRaster等接口（但没有实现IGeoDataset2、IRasterDataset接口）,空间分析模型,AE的GeoAnalyst库用于进行栅格空间分析它由两大类对象构成：环境支持对象分析操作对象,空间分析步骤,获取License设置分析环境访问输入数据执行分析操作使用输出结果,获取License,publicvoidGetSpatialAnalystLicense()/GetSpatialAnalystextensionuniqueidentifier(UID).UIDpUID=newUIDClass();pUID.Value=esriCore.SAExtension.1;/AddSpatialAnalystextensiontothelicensemanager.objectv=null;IExtensionManagerAdminextensionManagerAdmin=newExtensionManagerClass();extensionManagerAdmin.AddExtension(pUID,refv);/Enablethelicense.IExtensionManagerextensionManager=(IExtensionManager)extensionManagerAdmin;IExtensionextension=extensionManager.FindExtension(pUID);IExtensionConfigextensionConfig=(IExtensionConfig)extension;if(!(extensionConfig.State=esriExtensionState.esriESUnavailable)extensionConfig.State=esriExtensionState.esriESEnabled;elseMessageBox.Show(NoSpatialAnalystLicenseavailable);,设置分析环境,通过RasterAnalysisClass来实现。4个主要环境属性CellSize：输出精度Extent：分析操作发生区域Mask：在Extent基础上确定分析操作针对的区域SpatialReference其他环境属性与具体操作有关,默认值,Cellsize输入数据集中的最大的CellSize值Extent输入数据集的Extent的交集Mask无OutSpatialReference使用第一个有SpatialReference的输入Raster的SpatialReference。建议所有栅格使用相同的SpatialReferenceOutWorkspace由系统环境变量%TEMP%指定,设置分析环境,publicIRasterAnalysisEnvironmentSetNewDefaultEnvironment(IEnvelopeenvelope_Extent,doublenCellSize,IGeoDatasetgeoDataset_Mask,IWorkspaceworkspace,ISpatialReferencespatialReference)IRasterAnalysisEnvironmenttempSetNewDefaultEnvironment=null;IRasterAnalysisEnvironmentrasterAnalysisEnvironment=newRasterAnalysisClass();if(envelope_Extent!=null)objectextentProvider=(object)envelope_Extent;objectsnapRasterData=Type.Missing;rasterAnalysisEnvironment.SetExtent(esriRasterEnvSettingEnum.esriRasterEnvValue,refextentProvider,refsnapRasterData);objectcellSizeProvider=(object)nCellSize;rasterAnalysisEnvironment.SetCellSize(esriRasterEnvSettingEnum.esriRasterEnvValue,refcellSizeProvider);rasterAnalysisEnvironment.Mask=geoDataset_Mask;rasterAnalysisEnvironment.OutWorkspace=workspace;rasterAnalysisEnvironment.OutSpatialReference=spatialReference;rasterAnalysisEnvironment.SetAsNewDefaultEnvironment();returnrasterAnalysisEnvironment;,访问输入数据,4种可接受的输入RasterDataset：由RasterBand构成RasterBandRasterRasterDescriptor：只对子集操作时使用另两种可接受的输入FeatureClassFeatureClassDescriptor这两种输入会根据环境参数自动转换为栅格。,创建RasterDataset,publicIRasterDatasetOpenRasterDataset(stringsPath,stringsFileName)IRasterDatasetrasterDataset=null;IWorkspaceFactoryworkspaceFactory=newRasterWorkspaceFactoryClass();IRasterWorkspacerasterWorkspace=null;if(workspaceFactory.IsWorkspace(sPath)rasterWorkspace=(IRasterWorkspace)(workspaceFactory.OpenFromFile(sPath,0);rasterDataset=rasterWorkspace.OpenRasterDataset(sFileName);returnrasterDataset;,创建RasterDescriptor,publicIRasterDescriptorCreateRasterDescriptor(stringsPath,stringsFileName,stringsWhereClause,stringsSubField,stringsInField)IRasterDescriptorrasterDescriptor=newRasterDescriptorClass();IQueryFilterqueryFilter=newQueryFilterClass();queryFilter.WhereClause=sWhereClause;queryFilter.SubFields=sSubField;IRasterDatasetrasterDataset=OpenRasterDataset(sPath,sFileName);IRasterraster=rasterDataset.CreateDefaultRaster();rasterDescriptor.Create(raster,queryFilter,sInField);returnrasterDescriptor;,执行分析操作,分析操作有很多，但用法类似。须先知道分析所用的接口，然后调用接口函数执行分析时可修改环境参数,voidSlope()IRasterDatasetrasterDataset_Elevation=OpenRasterDataset(D:SpatialTest,elevation);ISurfaceOpsurfaceOp=newRasterSurfaceOpClass();IGeoDatasetgeoDataset_Elevation=(IGeoDataset)rasterDataset_Elevation;System.ObjectzFactor=Type.Missing;IGeoDatasetgeoDataset_Slope=surfaceOp.Slope(geoDataset_Elevation,esriGeoAnalysisSlopeEnum.esriGeoAnalysisSlopeDegrees,refzFactor);,执行时修改环境参数,voidMakeConstantRaster()IRasterMakerOprasterMakerOp=newRasterMakerOpClass();IRasterAnalysisEnvironmentrasterAnalysisEnvironment=(IRasterAnalysisEnvironment)rasterMakerOp;IWorkspaceFactoryworkspaceFactory=newRasterWorkspaceFactoryClass();IWorkspaceworkspace=workspaceFactory.OpenFromFile(c:temp,0);rasterAnalysisEnvironment.OutWorkspace=workspace;objectobject_cellSize=(System.Object)30;rasterAnalysisEnvironment.SetCellSize(esriRasterEnvSettingEnum.esriRasterEnvValue,refobject_cellSize);IEnvelopeenvelope=newEnvelopeClass();envelope.XMin=0;envelope.YMin=0;envelope.XMax=3000;envelope.YMax=3000;objectextentProvider=(System.Object)envelope;objectobject_Missing=System.Type.Missing;rasterAnalysisEnvironment.SetExtent(esriRasterEnvSettingEnum.esriRasterEnvValue,refextentProvider,refobject_Missing);IRasterraster=null;raster=(IRaster)(rasterMakerOp.MakeConstant(10,true);,显示输出结果,publicvoidAddRasterLayer(IRasterraster)IRasterLayerrasterLayer=newRasterLayerClass();rasterLayer.CreateFromRaster(raster);m_mapControl.AddLayer(rasterLayer,0);m_mapControl.ActiveView.Refresh();,保存结果,publicvoidMakePermanent(IRasterraster)IRasterBandCollectionrasterBandCollection=(IRasterBandCollection)raster;IRasterBandrasterBand=rasterBandCollection.Item(0);IRasterDatasetrasterDataset=rasterBand.RasterDataset;ITemporaryDatasettemporaryDataset=(ITemporaryDataset)rasterDataset;IWorkspaceFactoryworkspaceFactory=newRasterWorkspaceFactoryClass();IWorkspaceworkspace=workspaceFactory.OpenFromFile(c:temp,0);/FormatcanbeGRID,TIFF,orIMAGINEImage.temporaryDataset.MakePermanentAs(Result2.img,workspace,IMAGINEImage);,表面分析ISurfaceOp,Slope：坡度计算：Aspect：坡向计算Contour：生成等值线HillShade：山体阴影分析Visibility：通视分析Curvature：曲率分析,栅格变换ITransformationOp,Clip：裁剪Flip