AE山歌数据加载

原文：http://blog.sina.com.cn/s/blog_66a98e7d0100jho0.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);

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 

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 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; 
}

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; 

}