ArcGIS鏍呮牸澶勭悊鎬荤粨 - 鐧惧害鏂囧簱

ILogicalOp pLogicalop = newRasterMathOpsClass();//获得ILogicalop接口，用于数学运算

IRaster pOutr = pLogicalop.IsNull(pRaster asIGeoDataset ) asIRaster ;//如果数据缺失，那么输出为1，否则输出为0.

Con可以将栅格数据中的某些值（通过条件查询）设置为想要的区域，将某些不想要的区域设置为其它值（可

以是自己设置的也可以是输入的固定值）

IConditionalOp:方法Con， IConditionalOp.

Con(IGeoDatasetconditionalRaster,IGeoDatasettrueRaster, ref objectfalseRaster)方法：

不管conditionalRaster

是仅有0和1的值，还是有多个值的栅格数据，

0的栅格像

只要是值大于0的栅格像素值，赋的值都是trueRaster，凡是值等于

素值那么赋值为falseRaster，falseRaster可以为一个常数，也可以为一个栅格数据集（Raster）对应的像素值。

IConditionalOp. Con代码

IWorkspaceFactory pWksfact = newRasterWorkspaceFactoryClass(); IRasterWorkspace pRwks = pWksfact.OpenFromFile(@\栅格数据处理集\\Temp\\data\, 0)

asIRasterWorkspace ;

IRaster pRaster = pRwks.OpenRasterDataset(\).CreateDefaultRaster(); IRaster pSraster = newRasterClass(); //object pint = 100;//object为常数

object pRa = pRaster;//object为栅格数据集

IConditionalOp pConditionalop = newRasterConditionalOpClass();

//pSraster = pConditionalop.Con(pRaster as IGeoDataset, pRaster as IGeoDataset , ref pint) as IRaster ;//object为常数

pSraster = pConditionalop.Con(pRaster asIGeoDataset, pRaster asIGeoDataset, ref pRa) asIRaster;//object为栅格数据集 ISaveAs pSa = pSraster asISaveAs;

pSa.SaveAs(\, pRwks asIWorkspace, \);

使用“设为空函数”将值设置为 NoData：在spatial analyst下的conditional下的set null。

要将值大于 5 的像元设置为 NoData，并且保留其他像元的原始值，请在工具对话框中使用以下参数： 输入条件栅格：InRas1 表达式：\条件)

求值结果为 False 的输入栅格或常数值：InRas1（即不符合条件的像素值设置为输入栅格对应的值） 输出栅格：setnull_1

IConditionalOp:只是针对栅格数据只有两个值的0和1的栅格，如果只有0和1，那么将值为1的设置为空，值为0的仍然为0，或者是其它栅格（False Raster）数据相应位置的值。或者栅格数据有多个值，0和大于0两类，当栅格数据有多个值时，值大于0的设置为空，值等于0的仍然是0或者是其它栅格数据（False Raster）相应位置的值。和conditional下的set null理解差不多，但是有区别，不能设置”sql语句”。将大于0的值变为nodata，将等于0的值变为falseraster的栅格像素值。 用到的接口是 IConditionalOp方法是：SetNull

相应 的代码：

IWorkspaceFactory pWksfact = newRasterWorkspaceFactoryClass();

IRasterWorkspace pRwks = pWksfact.OpenFromFile(@\,0) asIRasterWorkspace ; IRaster2 pRaster = pRwks.OpenRasterDataset(\).CreateDefaultRaster()

asIRaster2;

IRaster2 pR2 = pRwks.OpenRasterDataset(\).CreateDefaultRaster() asIRaster2; IConditionalOp pCondi = newRasterConditionalOpClass(); IGeoDataset pDataset = pRaster asIGeoDataset; IGeoDataset pFdataset = pR2 asIGeoDataset;

IGeoDataset pOutdataset = pCondi.SetNull(pDataset ,pFdataset ); ISaveAs pSa = pOutdataset asISaveAs;

pSa.SaveAs( \,pRwks asIWorkspace ,\ );

通过一个面的范围来提取栅格数据：

IWorkspaceFactory pWksfact = newRasterWorkspaceFactoryClass();

IRasterWorkspace pRwks = pWksfact.OpenFromFile(@\,0) asIRasterWorkspace ; IRaster2 pRaster = pRwks.OpenRasterDataset(\).CreateDefaultRaster() asIRaster2;

IRasterProps pRprops = pRaster asIRasterProps ;

IExtractionOp pExtra = newRasterExtractionOpClass();

IWorkspaceFactory pSwksfact = newShapefileWorkspaceFactoryClass(); IFeatureWorkspace pFwks = pSwksfact.OpenFromFile(@\, 0) asIFeatureWorkspace ;

IFeatureClass pFclass = pFwks.OpenFeatureClass(\); IFeatureCursor pFcur = pFclass.Search(null,false ); IFeature pFeature = pFcur.NextFeature();

IPolygon pPolygon = pFeature.Shape asIPolygon ;

IWorkspace pOutwks = pWksfact.OpenFromFile(@\, 0); IGeoDataset pGeodataset = pRaster asIGeoDataset;

IGeoDataset pOutgd = pExtra.Polygon(pGeodataset ,pPolygon,true ) asIGeoDataset ;//true指的是面内的栅格提取出来，false指的是面外的栅格数据提取出来， IRaster pOutr = pOutgd asIRaster;//将Geodataset转换为iraster，而不是转换为irasterdataset，用isaveas来保存存储在内存中的栅格数据。 ISaveAs pSa = (ISaveAs ) pOutr ;

pSa.SaveAs(\, pOutwks, \);//poutwks一定要是栅格工作空间工厂打开的工作空间，不能是其它工作空间工厂打开的工作空间。

通过属性提取栅格数据

IWorkspaceFactory pWksfact = newRasterWorkspaceFactoryClass();

IRasterWorkspace pRwks = pWksfact.OpenFromFile(@\,0) asIRasterWorkspace ; IRaster2 pRaster = pRwks.OpenRasterDataset(\).CreateDefaultRaster() asIRaster2;

IRasterProps pRprops = pRaster asIRasterProps ;

IExtractionOp pExtra = newRasterExtractionOpClass();

IQueryFilter pQueryfilter = newQueryFilterClass () ;//属性查询，查询到属性值是多少的像素。

pQueryfilter.WhereClause = \;//设置像素查询的条件。

IRasterDescriptor pRdescriptor = newRasterDescriptorClass();//栅格描述接口。 pRdescriptor.Create(pRaster asIRaster, pQueryfilter, \); IWorkspaceFactory pRwks2 = newRasterWorkspaceFactoryClass(); IWorkspace pWks2 = pRwks2.OpenFromFile(@\, 0);

IRaster pOut2 = pExtra.Attribute(pRdescriptor) asIRaster;//将获得的栅格数据给iraster

ISaveAs poUTas = pOut2 asISaveAs ;

poUTas.SaveAs(\,pWks2 ,\);

通过范围（Rectangle）来提取栅格数据

IWorkspaceFactory pWksfact = newRasterWorkspaceFactoryClass();

IRasterWorkspace pRwks = pWksfact.OpenFromFile(@\,0) asIRasterWorkspace ; IRaster2 pRaster = pRwks.OpenRasterDataset(\).CreateDefaultRaster() asIRaster2;

IRasterProps pRprops = pRaster asIRasterProps ;

IWorkspaceFactory pSwksfact = newShapefileWorkspaceFactoryClass(); IFeatureWorkspace pFwks = pSwksfact.OpenFromFile(@\, 0) asIFeatureWorkspace ;

IFeatureClass pFclass = pFwks.OpenFeatureClass(\); IFeatureCursor pFcur = pFclass.Search(null, false); IFeature pFeature = pFcur.NextFeature(); IEnvelope pEnv = pFeature.Extent; //获取范围

IExtractionOp pEx = newRasterExtractionOpClass();

IRaster pOraster = pEx.Rectangle(pRaster asIGeoDataset, pEnv, true) asIRaster ; ISaveAs pSa = pOraster asISaveAs;//保存

pSa.SaveAs(\,pRwks asIWorkspace ,\);

通过矩形（Rectangle）来导出

地图坐标最小X、Y值在左下角，IEnvelope最小值是左下角，最大值是右上角，栅格数据最小行列值是在左上角，最大行列值是在右下角。 double pXmin, pXmax, pYmin, pYmax; IEnvelope pEnv = newEnvelopeClass();

pR2.PixelToMap(pW, pH + pRprops.Height, out pXmin, out pYmin);//获得xy值的最小值 pR2.PixelToMap(pW + pRprops.Width ,pH,out pXmax ,out pYmax );//获得xy值得最大值 pEnv.PutCoords(pXmin, pYmin, pXmax, pYmax);//设置IEnvelope的范围 IExtractionOp pExtractop = newRasterExtractionOpClass();

IRaster pSraster = pExtractop.Rectangle(pR asIGeoDataset, pEnv, true) asIRaster; ISaveAs pSa = pSraster asISaveAs;

pSa.SaveAs(\ + Pc , pRwks asIWorkspace, \);

通过栅格数据提取栅格数据

IWorkspaceFactory pWksfact = newRasterWorkspaceFactoryClass();