摘要:ArcGIS使用者经常要面对大量的数据处理工作,如果要在自己的程序中使用Geoprocessing,更多的时候我们是要进行对数据进行批处理分析,Geoprocessing为我们提供了丰富的支持批处理的功能。
摘要:ArcGIS使用者经常要面对大量的数据处理工作,如果要在自己的程序中使用Geoprocessing,更多的时候我们是要进行对数据进行批处理分析,Geoprocessing为我们提供了丰富的支持批处理的功能。1.工作空间中查询所需数据
2.模型处理过程中各种输入数据的处理
3.枚举、循环执行
--------------------
1.工作空间中查询所需数据
要对数据进行批处理操作,首先需要知道工作空间中有哪些数据,怎么从工作空间大量数据中提取出我们所需要的数据。GeoProcessor类为我们提供了一些提取数据的方法。
listDatasets (string wildCard, string datasetType)
listFeatureClasses (string wildCard, string featureType, string dataset)
listRasters (string wildCard, string rasterType)
listTables (string wildCard, string tableType)
listToolboxes(string wildCard)
listWorkspaces (string wildCard, string workspaceType)
看看代码段怎么写:
- //list all the featureClasses starting with c
- gp.setEnvironmentValue("workspace", inputWorkspace);
- IGpEnumList featureClasses = gp.listFeatureClasses("c*", "", "");
- String featureClass = featureClasses.next();
- System.out.println("-----------Feature Classes starting with c-----------");
- while (! "".equals(featureClass)) {
-
- System.out.println(featureClass);
-
- featureClass = featureClasses.next();
- }
再参考另外两个例子,相信对在工作空间中查询数据会有更多的认识。
返回所有面状要素
- System.out.println("\n-----------Polygon Feature Classes-----------");
- gp.setEnvironmentValue("workspace", inputWorkspace);
- featureClasses = gp.listFeatureClasses("", "polygon", "");
- featureClass = featureClasses.next();
- while (! "".equals(featureClass)) {
-
- System.out.println(featureClass);
-
- featureClass = featureClasses.next();
- }
- // List all TIF files in the workspace and build pyramids
- gp.setEnvironmentValue("workspace", inputWorkspace);
- IGpEnumList rasters = gp.listRasters("", "TIF");
- String raster = rasters.next();
- BuildPyramids buildPyramids = new BuildPyramids(raster);
- while (! "".equals(raster)) {
-
- System.out.println("\n------------Building pyramids for: " + raster + "----------");
-
- gp.execute(buildPyramids, null);
-
- raster = rasters.next();
- }
Method Type Keywords
ListDatasets All, Feature, Coverage, RasterCatalog, CAD, VPF, TIN, Topology
ListFeatureClasses All, Point, Label, Node, Line, Arc, Route, Polygon, Region
ListFields All, SmallInteger, Integer, Single, Double, String, Date, OID, Geometry, Blob
ListWorkspaces All, Coverage, Access, SDE, Folder
ListTables All, dBASE, INFO
ListRasters All, ADRG, BIL, BIP, BSQ, BMP, CADRG, CIB, ERS, GIF, GIS, GRID, STACK, IMG, JPEG, LAN, SID, SDE, TIF, RAW, PNG, NITF
2.模型处理过程中各种输入数据的处理
Geoprocessing计算过程中会要求多个输入,通常可以用IGpEnumList来捕获。
- gp.setEnvironmentValue("workspace", multiWorkspace);
- IGpEnumList polygonFCs = gp.listFeatureClasses("", "polygon", "");
- String polygon = polygonFCs.next();
- String polygonsToUnion = "";
- while (! "".equals(polygon)){
-
- polygonsToUnion += polygon;
-
- polygon = polygonFCs.next();
- if (! "".equals(polygon)){
-
- polygonsToUnion += ";";
- }
- }
- Union union = new Union(polygonsToUnion,outputWorkspace+"/unioned.shp");
- gp.execute(union, null);
- // List all feature classes in the workspace.
- gp.setEnvironmentValue("workspace", multiWorkspace);
- IGpEnumList polygonFCs = gp.listFeatureClasses("", "polygon", "");
- //make the value table
- GPValueTable gpValueTable = new GPValueTable();
- String polygon = polygonFCs.next();
- String row = null;
- while (! "".equals(polygon)){
-
- if ("center".equals(polygon)){
-
- row = polygon + " 1";
-
- } else {
-
- row = polygon + " 2";
- }
- gpValueTable.addRow(row);
- polygon = polygonFCs.next();
- }
- Union union = new Union(gpValueTable, outputWorkspace+"/unionedValueTable.shp");
- gp.execute(union, null);
前面两点都是针对一个Geoprocessing操作而言,如果需要多个操作,可以用基本程序语言来描述,这分为两种情况,一是多种Geoprocessing的数据处理,一种是同一Geoprocessing循环执行,相比ArcToolbox而言,这里体现的是程序代码带给我们的方便。