private ISimpleSurface GetRasterSurface(
[NotNull] IRaster sourceRaster,
[NotNull] IEnvelope box,
[CanBeNull] out IDataset memoryRasterDataset)
{
// Remark:
// surface values outside 'raster'.envelope (but within 'box') are 0
Assert.ArgumentNotNull(sourceRaster, nameof(sourceRaster));
Assert.ArgumentNotNull(box, nameof(box));
IRasterFunction rasterFunction = new ClipFunctionClass();
IClipFunctionArguments functionArguments = new ClipFunctionArgumentsClass();
functionArguments.Raster = sourceRaster;
IEnvelope clipBox = GetClipBox(box, sourceRaster);
functionArguments.Extent = clipBox;
functionArguments.ClippingGeometry = clipBox;
functionArguments.ClippingType = esriRasterClippingType.esriRasterClippingOutside;
IFunctionRasterDataset functionRasterDataset = new FunctionRasterDataset();
functionRasterDataset.Init(rasterFunction, functionArguments);
functionRasterDataset.RasterInfo.NoData = (float)-9999;
// unsicher, wie die memory verwaltung ist
// zum sicherstellen der memory-verwaltung
// --> inmemory raster erstellen
var save = (ISaveAs2)functionRasterDataset;
IWorkspaceName wsName = WorkspaceUtils.CreateInMemoryWorkspace("raster");
var ws = (IWorkspace)((IName)wsName).Open();
save.SaveAs("clipped", ws, "MEM");
IRasterDataset rasterDataset = ((IRasterWorkspace2)ws).OpenRasterDataset("clipped");
IRaster rasterData = rasterDataset.CreateDefaultRaster();
// Problems and workarounds for raster(-mosaic) data in surfaces
// -------------------------------------------------------------
//
// Extent completly within footprint of mosaic dataset: -> no NoDataValues -> no problems
// Extent partly within footprint of mosaic dataset : -> double.NaN returned for values outside footprint -> no problems (TODO: verifiy)
// Extent completely outside footprint of mosaic dataset, but within extent of mosaic data set:
// 0-values returned for Null-raster values
// workaround: ((IRasterProps) rasterData).NoDataValue = (float)0; works, if ((IRasterProps) raster).NoDataValue = null and no Height == 0
// workaround to test: use CustomPixelFilter (see https://github.com/Esri/arcobjects-sdk-community-samples/tree/master/Net/Raster/CustomNodataFilter/CSharp
// Extent completely outside extent of mosaic dataset
// 0-values returned for Null-raster values, rasterData.Height = 1, rasterData.Width = 1
// workaround 1: use custom RasterSurface class.
// workaround 2: ((IRasterProps) rasterData).NoDataValue = (float)0; works, if ((IRasterProps) raster).NoDataValue = null and no Height == 0
memoryRasterDataset = (IDataset)rasterDataset;
ISimpleSurface rasterSurface = RasterReference.CreateSurface(rasterData);
return(rasterSurface);
}
/// <summary>
/// Clips a raster to the boundary of a polygon
/// </summary>
/// <param name="inRaster">IRaster, IRasterDataset, or string</param>
/// <param name="geo">Polygon Geometry</param>
/// <param name="clipType">the type of clip either inside or outside</param>
/// <returns></returns>
public IFunctionRasterDataset clipRasterFunction(object inRaster, IGeometry geo, esriRasterClippingType clipType)
{
IFunctionRasterDataset rRst = createIdentityRaster(inRaster);
IRaster2 rRst2 = (IRaster2)createRaster(rRst);
string tempAr = funcDir + "\\" + FuncCnt + ".afr";
IFunctionRasterDataset frDset = new FunctionRasterDatasetClass();
IFunctionRasterDatasetName frDsetName = new FunctionRasterDatasetNameClass();
frDsetName.FullName = tempAr;
frDset.FullName = (IName)frDsetName;
IRasterFunction rsFunc = new ClipFunctionClass();
IEnvelope env = geo.Envelope;
double hX = rRst.RasterInfo.CellSize.X / 2;
double hY = rRst.RasterInfo.CellSize.Y / 2;
double xMin = env.XMin;
double xMax = env.XMax;
double yMin = env.YMin;
double yMax = env.YMax;
int clm, rw;
rRst2.MapToPixel(xMin, yMin,out clm,out rw);
rRst2.PixelToMap(clm, rw, out xMin, out yMin);
xMin = xMin - hX;
yMin = yMin - hY;
rRst2.MapToPixel(xMax, yMax, out clm, out rw);
rRst2.PixelToMap(clm, rw, out xMax, out yMax);
xMax = xMax + hX;
yMax = yMax + hY;
env.PutCoords(xMin, yMin, xMax, yMax);
IClipFunctionArguments args = new ClipFunctionArgumentsClass();
args.Extent = env;
args.ClippingGeometry = geo;
args.ClippingType = clipType;
args.Raster = rRst;
frDset.Init(rsFunc, args);
return frDset;
}
