根据栅格数据的范围和像元大小生成等比例的矢量数据

为啥会有这么一个需求呢，后面要是继续写的话会详细说，首先是有一个栅格数据，比如这样的：

我的目标是这样的（矢量），

就是这样，上面的栅格数据像大小是2*2的，直接上代码：

string fileNameRaster = System.IO.Path.GetFileName(rasterPath);

IWorkspaceFactory pWorkspaceFactory = new RasterWorkspaceFactory();

string projectPath = System.IO.Path.GetDirectoryName(rasterPath);

IWorkspace rWorkspace = pWorkspaceFactory.OpenFromFile(projectPath, 0);

IRasterWorkspace pRasterWorkspace = rWorkspace as IRasterWorkspace;

IRasterDataset pRasterDataset = pRasterWorkspace.OpenRasterDataset(fileNameRaster);

IRasterLayer pRasterLayer = new RasterLayerClass();

pRasterLayer.CreateFromDataset(pRasterDataset);

IRaster pRaster = pRasterLayer.Raster;

IRasterProps pRasterProps = (IRasterProps)pRaster;

double xMin = pRasterProps.Extent.XMin;

double xMax = pRasterProps.Extent.XMax;

double yMin = pRasterProps.Extent.YMin;

double yMax = pRasterProps.Extent.YMax;

int dHeight = pRasterProps.Height;//当前栅格数据集的行数

int dWidth = pRasterProps.Width; //当前栅格数据集的列数

int count = dHeight * dWidth;//网格数据的总数

double dX = pRasterProps.MeanCellSize().X; //栅格的宽度

double dY = pRasterProps.MeanCellSize().Y; //栅格的高度

IRaster2 raster2 = pRaster as IRaster2;

object o = Type.Missing;

//这个CreateFeatureClass（）方法就是创建一个featureclass,我就不贴代码了，网上很多

IFeatureClass pfeatureClass = CreateFeatureClass(System.IO.Path.GetDirectoryName(rasterPath), System.IO.Path.GetFileNameWithoutExtension(rasterPath));

if (pfeatureClass != null)

{

for (int i = 0; i < dHeight; i++)

{

double x0 = xMin;

double y0 = yMax - dY * i;

for (int j = 0; j < dWidth; j++)

{

IGeometry geo = new PolygonClass();

IPolygon polygon = new PolygonClass();

IGeometryCollection pGeomCol = polygon as IGeometryCollection;

IFeature pfeature = pfeatureClass.CreateFeature();

//xMIN, yMax,

IRing pRing = new RingClass();

IPointCollection pPointMulti = pRing as IPointCollection;

//左上

IPoint pPoint0 = new PointClass();

pPoint0.PutCoords(x0 + dX * j, y0);

pPointMulti.AddPoint(pPoint0, ref o, ref o);

//右上

IPoint pPoint1 = new PointClass();

pPoint1.PutCoords(x0 + dX * (j + 1), y0);

pPointMulti.AddPoint(pPoint1, ref o, ref o);

//右下

IPoint pPoint2 = new PointClass();

pPoint2.PutCoords(x0 + dX * (j + 1), y0 - dY);

pPointMulti.AddPoint(pPoint2, ref o, ref o);

//左下

IPoint pPoint3 = new PointClass();

pPoint3.PutCoords(x0 + dX * j, y0 - dY);

pPointMulti.AddPoint(pPoint3, ref o, ref o);

//关闭的点

IPoint pPoint4 = new PointClass();

pPoint4.PutCoords(x0 + dX * j, y0);

pPointMulti.AddPoint(pPoint4, ref o, ref o);

pRing.Close();

if (!pRing.IsExterior)

{

pRing.ReverseOrientation();

}

pGeomCol.AddGeometry(pRing, ref o, o);

ITopologicalOperator topo = polygon as ITopologicalOperator;

topo.Simplify();

geo = polygon;

int numIndex = pfeature.Fields.FindField("number");

int pixelIndex = pfeature.Fields.FindField("pixelValue");

int num = i * dWidth + j;

pfeature.set_Value(numIndex, num);

//0，列号，行号

// object value = raster2.GetPixelValue(0, j, i);

//pfeature.set_Value(pixelIndex, value);

pfeature.Shape = geo as IPolygon;

pfeature.Store();

}

}

}

大概的实现的思路就是以栅格数据的左上角为顶点，先创建一行的数据，因为像元大小为2，point0-point3就是4个角点，左上，右上，右下，左下，需要注意，第一点跟最后一个点必须是同个点，就是把这个图形包起来（我的理解），所有就有了point4，之后依次遍历，一行遍历之后，开始下一个循环，你的左上角的起始顶点变成了上个图形的左下角的坐标。再次循环就可以了，实现思路就是这样。

PS：网格多了程序很耗时。