出处：http://www.cnblogs.com/linghe/archive/2009/02/09/1386843.html
两个星期以来一直与栅格数据打交道，对AO的栅格部分应该有了一定的理解，下面是自己的一点体会，希望高手指教：－）
1、栅格数据的存储类型
栅格数据一般可以存储为ESRI GRID（由一系列文件组成），TIFF格式（包括一个TIF文件和一个AUX文件），IMAGINE Image格式 在AE中一般调用ISaveAs接口来保存栅格数据
2、栅格数据集和栅格编目的区别
一个栅格数据集由一个或者多个波段（RasterBand）的数据组成，一个波段就是一个数据矩阵。对于格网数据（DEM数据）和单波段的影像数据，表现为仅仅只有一个波段数据的栅格数据集，而对于多光谱影像数据则表现为具有多个波段的栅格数据集
栅格编目（RasterCatalog）用于显示某个研究区域内各种相邻的栅格数据，这些相邻的栅格数据没有经过拼接处理合成一副大的影像图
3、IRasterWorkspaceEx与IRasterWorkspace ,IRsterWorkspace2的区别
1).IRasteWorkspaceEx接口主要是用来读取GeoDatabase中的栅格数据集和栅格编目
2) . IRasterWorkspace ,IRsterWorkspace2主要是用来读取以文件格式存储在本地的栅格数据
4、加载栅格数据（以存储在本地的栅格数据文件为例）
1.直接用IRasterLayer接口打开一个栅格文件并加载到地图控件
IRasterLayer rasterLayer = new RasterLayerClass();
rasterLayer.CreateFromFilePath(fileName); // fileName指存本地的栅格文件路径
axMapControl1.AddLayer(rasterLayer, 0);
2. 用IRasterDataset接口打开一个栅格数据集
IWorkspaceFactory workspaceFactory = new RasterWorkspaceFactory();
IWorkspace workspace;
workspace = workspaceFactory.OpenFromFile(inPath, 0); //inPath栅格数据存储路径
if (workspace == null)
{
Console.WriteLine("Could not open the workspace.");
return;
}
IRasterWorkspace rastWork = (IRasterWorkspace)workspace;
IRasterDataset rastDataset;
rastDataset= rastWork.OpenRasterDataset(inName);//inName栅格文件名
if (rastDataset == null)
{
Console.WriteLine("Could not open the raster dataset.");
return;
}
5、如何读取栅格数据的属性和遍历栅格数据
栅格数据的属性包括栅格大小，行数，列数，投影信息，栅格范围等等，见下面代码
（假设当前加载的栅格文件栅格值存储方式为：UShort类型）
IRasterProps rasterProps = (IRasterProps)clipRaster;
int dHeight = rasterProps.Height;//当前栅格数据集的行数
int dWidth = rasterProps.Width; //当前栅格数据集的列数
double dX = rasterProps.MeanCellSize().X; //栅格的宽度
double dY = rasterProps.MeanCellSize().Y; //栅格的高度
IEnvelope extent=rasterProps.Extent; //当前栅格数据集的范围
rstPixelType pixelType=rasterProps.PixelType; //当前栅格像素类型
IPnt pntSize = new PntClass();
pntSize.SetCoords(dX, dY);
IPixelBlock pixelBlock = clipRaster.CreatePixelBlock(pntSize);
IPnt pnt = new PntClass();
for (int i = 0; i < dHeight; i++)
for (int j = 0; j < dWidth; j++)
{
pnt.SetCoords(i, j);
clipRaster.Read(pnt, pixelBlock);
if (pixelBlock != null)
{
object obj = pixelBlock.GetVal(0, 0, 0);
MessageBox.Show( Convert.ToUInt32(obj).ToString());
}
}
6、如何提取指定的范围的栅格数据
提取指定范围内的栅格数据通常用两种方法IRasterLayerExport(esriCarto), IExtractionOp, IExtractionOp2 (esriSpatialAnalyst)，IRasterLayerExport接口提供的栅格数据提取功能有限，只能以矩形范围作为提取范围，而IExtractionOp接口提供了多边形，圆，属性，矩形等几种形式作为提取栅格数据.
1).IRasterLayerExport接口
IRasterLayerExport rLayerExport = new RasterLayerExportClass();
rLayerExport.RasterLayer = rasterLayer;// rasterLayer指当前加载的栅格图层
rLayerExport.Extent = clipExtent;//clipExtent指提取栅格数据的范围
if (proSpatialRef != null)
rLayerExport.SpatialReference = proSpatialRef;// proSpatialRef当前栅格数据的投影信息
IWorkspaceFactory pWF = new RasterWorkspaceFactoryClass();
try
{
IWorkspace pRasterWorkspace = pWF.OpenFromFile(_folder, 0);// _folder指栅格文件保存路径
IRasterDataset outGeoDataset = rLayerExport.Export(pRasterWorkspace, code, strRasterType);
//调用ISaveAs接口将导出的数据集保存
……………………..
}
Catch(Exception ex)
{
Throw new Argumention(ex.Message);
}
2．IExtractionOp接口(调用此接口前，应该先检查空间许可)
IExtractionOp extraction = new RasterExtractionOpClass();
try
{
IGeoDataset geoDataset = extraction.Rectangle((IGeoDataset)clipRaster, clipExtent, true);
IRaster raster = geoDataset as IRaster;
if (raster != null)
{
IWorkspaceFactory WF = new RasterWorkspaceFactoryClass();
IWorkspace rasterWorkspace = WF.OpenFromFile(_folder, 0);
ISaveAs saveAs = (ISaveAs)raster;
saveAs.SaveAs(“Result.tif”, rasterWorkspace, "TIFF");
}
}
catch (Exception ex)
{
MessageBox..Show(Ex.message);
}
7．栅格数据重采样
栅格数据的重采样主要基于三种方法：最邻近采样（NEAREST），双线性
ILINEAR）和三次卷积采样（CUBIC）。
（1）.最邻近采样：它用输入栅格数据中最临近栅格值作为输出值。因此，在重采
样后的输出栅格中的每个栅格值, 都是输入栅格数据中真实存在而未加任何改变的值。这种方法简单易用，计算量小，重采样的速度最快。
（2）.双线性采样：此重采样法取待采样点（x，y）点周围四个邻点，在y方向（或X方向）内插两次，再在x方向（或y方向）内插一次，得到（x，y）点的栅格值。
（3）.三次卷积采样：这是进一步提高内插精度的一种方法。它的基本思想是增加邻点来获
得最佳插值函数。取待计算点周围相邻的16个点，与双线性采样类似，可先在某一方向上内插，如先在x方向上，每四个值依次内插四次，再根据四次的计算结果在y方上内插，最终得到内插结果
代码示例：采用双线性采样
IRasterGeometryProc rasterGeometryProc = new RasterGeometryProcClass();
rasterGeometryProc.Resample(rstResamplingTypes.RSP_CubicConvolution, newCellSize, clipRaster);
Tag标签: 栅格数据 ArcEngine
栅格数据重分类 (2009-01-10 10:10:09) 标签：栅格 重分类 分类：AE二次开发
Code public static IRasterLayer SetViewShedRenderer(IRaster pInRaster,string sField,string sPath) { IRasterDescriptor pRD = new RasterDescriptorClass(); pRD.Create(pInRaster, new QueryFilterClass(), sField); IReclassOp pReclassOp = new RasterReclassOpClass(); IGeoDataset pGeodataset=pInRaster as IGeoDataset; IRasterAnalysisEnvironment pEnv = pReclassOp as IRasterAnalysisEnvironment; IWorkspaceFactory pWSF=new RasterWorkspaceFactoryClass(); IWorkspace pWS = pWSF.OpenFromFile(sPath, 0); pEnv.OutWorkspace = pWS; object objSnap = null; object objExtent = pGeodataset.Extent; pEnv.SetExtent(esriRasterEnvSettingEnum.esriRasterEnvValue, ref objExtent, ref objSnap); pEnv.OutSpatialReference = pGeodataset.SpatialReference; IRasterLayer pRLayer = new RasterLayerClass(); IRasterBandCollection pRsBandCol = pGeodataset as IRasterBandCollection; IRasterBand pRasterBand = pRsBandCol.Item(0); pRasterBand.ComputeStatsAndHist(); IRasterStatistics pRasterStatistic = pRasterBand.Statistics; double dMaxValue = pRasterStatistic.Maximum ; double dMinValue = pRasterStatistic.Minimum ; INumberRemap pNumRemap = new NumberRemapClass(); pNumRemap.MapRange(dMinValue, 0, 0); pNumRemap.MapRange(0, dMaxValue, 1); IRemap pRemap = pNumRemap as IRemap; IRaster pOutRaster = pReclassOp.ReclassByRemap(pGeodataset, pRemap, false) as IRaster ; pRLayer.CreateFromRaster(pOutRaster); return pRLayer; } 栅格图层和矢量图层的属性表浏览 if (pLyr is IFeatureLayer) { DataTable pTable = new DataTable(); IFeatureLayer pFealyr = pLyr as IFeatureLayer; IFeatureClass pFCls = pFealyr.FeatureClass; string shape = ""; if (pFCls.ShapeType == esriGeometryType.esriGeometryPoint) shape = "Point"; else if (pFCls.ShapeType == esriGeometryType.esriGeometryPolyline) shape = "Polyline"; else if (pFCls.ShapeType == esriGeometryType.esriGeometryPolygon) shape = "Polygon"; for (int i = 0; i < pFCls.Fields.FieldCount; i++) { pTable.Columns.Add(pFCls.Fields.get_Field(i).Name); } IFeatureCursor pCursor = pFCls.Search(null, false); int ishape = pFCls.Fields.FindField("Shape"); IFeature pFea = pCursor.NextFeature(); while (pFea != null) { DataRow pRow = pTable.NewRow(); for (int i = 0; i < pFCls.Fields.FieldCount; i++) { if (i == ishape) { pRow[i] = shape; continue; } pRow[i] = pFea.get_Value(i).ToString(); } pTable.Rows.Add(pRow); pFea = pCursor.NextFeature(); } dataGridView1.DataSource = pTable; } else if (pLyr is IRasterLayer) { IRasterLayer pRlyr = pLyr as IRasterLayer; IRaster pRaster = pRlyr.Raster; IRasterProps pProp = pRaster as IRasterProps; pProp.PixelType = rstPixelType.PT_LONG; if (pProp.PixelType == rstPixelType.PT_LONG) { IRasterBandCollection pBcol = pRaster as IRasterBandCollection; IRasterBand pBand = pBcol.Item(0); ITable pRTable = pBand.AttributeTable; DataTable pTable = new DataTable(); for (int i = 0; i < pRTable.Fields.FieldCount; i++) pTable.Columns.Add(pRTable.Fields.get_Field(i).Name); ICursor pCursor= pRTable.Search(null, false); IRow pRrow= pCursor.NextRow(); while (pRrow != null) { DataRow pRow = pTable.NewRow(); for (int i =0 ;i<pRrow .Fields .FieldCount ;i++) { pRow[i] = pRrow.get_Value(i).ToString () ; } pTable.Rows.Add(pRow); pRrow = pCursor.NextRow(); } dataGridView1.DataSource = pTable; } } 创建栅格数据集 (2008-04-20 14:14:05) 标签：arcgis engine c＃ 代码 it 分类：三文鱼的GIS 关键词：创建栅格数据集 IRasterWorkspace2 IRasterDataset CreateRasterDataset C# public IRasterDataset tin2raster(string tempBathyTIN,string geoPath, string gridName) { string tinFolder = System.IO.Path.GetDirectoryName(tempBathyTIN); string tinName = System.IO.Path.GetFileName(tempBathyTIN); IRasterDataset rasterDataset = new RasterDatasetClass(); try { string rasterPath = System.IO.Path.GetDirectoryName(geoPath); IWorkspaceFactory TinWF = new TinWorkspaceFactory(); ITinWorkspace TinWK = TinWF.OpenFromFile(tinFolder,0)as ITinWorkspace; ITinAdvanced2 tinAd = TinWK.OpenTin(tinName) as ITinAdvanced2; IEnvelope extent = tinAd.Extent; IPoint origin = extent.LowerLeft; origin.X = origin.X - (5 * 0.5); origin.Y = origin.Y - (5 * 0.5); int nCol = (int)Math.Round(extent.Width / 5) + 1; int nRow = (int)Math.Round(extent.Height / 5) +1; ISpatialReference2 spatialRef = (ISpatialReference2)extent.SpatialReference; IWorkspaceFactory rasterWF = new RasterWorkspaceFactoryClass(); IRasterWorkspace2 workSpace = (IRasterWorkspace2)rasterWF.OpenFromFile(rasterPath,0); rasterDataset = workSpace.CreateRasterDataset(gridName, "GRID", origin,nCol,nRow,5,5,1,ESRI.ArcGIS.Geodatabase.rstPixelType.PT_FLOAT, spatialRef,true); IRasterBandCollection bandColl = (IRasterBandCollection) rasterDataset; IRasterBand rasterBand = bandColl.Item(0); IRawPixels rawPixels = (IRawPixels)rasterBand; IPnt blockSize = new DblPntClass(); blockSize.X = nCol; blockSize.Y = nRow; IPixelBlock3 pixelBlock = (IPixelBlock3)rawPixels.CreatePixelBlock(blockSize); ITinSurface tinSurface = (ITinSurface)tinAd; IRasterProps rasterProps = (IRasterProps)rawPixels; object nodataFloat; //long nodataInt; object val = pixelBlock.get_PixelDataByRef(0); MessageBox.Show(val.ToString()); double cellsize = 5; origin.X = origin.X + (5 * 0.5); origin.Y = origin.Y + (5 * nRow) - (5 * 0.5); nodataFloat = Convert.ToDouble(rasterProps.NoDataValue.ToString()); tinSurface.QueryPixelBlock(origin.X,origin.Y,cellsize,cellsize,esriRasterizationType.esriElevationAsRaster,nodataFloat,val); IPnt offset = new DblPntClass(); offset.X = 0; offset.Y = 0; rawPixels.Write(offset,pixelBlock as IPixelBlock); } catch(Exception ex) { MessageBox.Show(ex.ToString()); } return rasterDataset; } public IRasterDataset CreateFileRasterDataset(string directoryName, string fileName) { // This function creates a new img file in the given workspace // and then assigns pixel values try { IRasterDataset rasterDataset = null; IPoint originPoint = new PointClass(); originPoint.PutCoords(0, 0); // Create the dataset IRasterWorkspace2 rasterWorkspace2 = null; rasterWorkspace2 = CreateRasterWorkspace(directoryName); rasterDataset = rasterWorkspace2.CreateRasterDataset(fileName, "IMAGINE Image", originPoint, 200, 100, 1, 1, 1, rstPixelType.PT_UCHAR, new UnknownCoordinateSystemClass(), true); IRawPixels rawPixels = null; IPixelBlock3 pixelBlock3 = null; IPnt pixelBlockOrigin = null; IPnt pixelBlockSize = null; IRasterBandCollection rasterBandCollection; IRasterProps rasterProps; // QI for IRawPixels and IRasterProps rasterBandCollection = (IRasterBandCollection)rasterDataset; rawPixels = (IRawPixels)rasterBandCollection.Item(0); rasterProps = (IRasterProps)rawPixels; // Create pixelblock pixelBlockOrigin = new DblPntClass(); pixelBlockOrigin.SetCoords(0, 0); pixelBlockSize = new DblPntClass(); pixelBlockSize.SetCoords(rasterProps.Width, rasterProps.Height); pixelBlock3 = (IPixelBlock3)rawPixels.CreatePixelBlock(pixelBlockSize); // Read pixelblock rawPixels.Read(pixelBlockOrigin, (IPixelBlock)pixelBlock3); // Get pixeldata array System.Object[,] pixelData; pixelData = (System.Object[,])pixelBlock3.get_PixelDataByRef(0); // Loop through all the pixels and assign value for (int i = 0; i < rasterProps.Width; i++) for (int j = 0; j < rasterProps.Height; j++) pixelData[i, j] = (i * j) % 255; // Write the pixeldata back System.Object cachePointer; cachePointer = rawPixels.AcquireCache(); rawPixels.Write(pixelBlockOrigin, (IPixelBlock)pixelBlock3); rawPixels.ReturnCache(cachePointer); // Return raster dataset return rasterDataset; } catch (Exception ex) { System.Diagnostics.Debug.WriteLine(ex.Message); return null; } } public IRasterWorkspace2 CreateRasterWorkspace(string pathName) { // Create RasterWorkspace IWorkspaceFactory workspaceFactory = new RasterWorkspaceFactoryClass(); return workspaceFactory.OpenFromFile(pathName, 0) as IRasterWorkspace2; }
转载于:https://www.cnblogs.com/willwayer/archive/2009/06/26/1511456.html
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