GPS软件应用 Geometry 对象浅析

GPS软件应用 Geometry 对象浅析

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来源:GPS之家-导航之家 作者:www.gpsuu.com 时间:2008-01-18

GPS软件应用 Geometry 对象浅析

ArcEngine Geometry库定义了基本几何图形的矢量表达形式，顶级的几何图形有Points、Multipoints、Polylines、Polygons、 Multipatches，Geodatabase和绘图系统使用这些几何图形来定义其他各种形状的特征和图形，提供了编辑图形的操作方法和地图符号系统 符号化特征数据的途径。

Geometry库中几个核心类和接口构成了Geometry对象的基本框架。

GeometryEnvironment

GeometryEnvironment提供了从不同的输入、设置或获取全局变量来创建几何图形的方法，以便控制geometry方法的行为。GeometryEnvironment对象是一个单例对象。

public IPolyline TestGeometryEnvironment()

private IPolygon GeometryBag_Example(IFeatureClass featureClass)

public IPolyline ConstructMultiPartPolyline(IPolyline inputPolyline)

public IMultiPatch CreateMultipatch()

//Prepare the geometry material list.

IGeometryMaterial texture = new GeometryMaterialClass();

texture.TextureImage = C:TempMyImage.bmp;

IGeometryMaterialList materialList = new GeometryMaterialListClass();

materialList.AddMaterial(texture);

//Create the multipatch.

IGeneralMultiPatchCreator multiPatchCreator = new GeneralMultiPatchCreatorClass();

multiPatchCreator.Init(4, 1, false, false, false, 4, materialList);

//Set up part.

//Could also use a Ring or a TriangleFan.

multiPatchCreator.SetPatchType(0, esriPatchType.esriPatchTypeTriangleStrip);

multiPatchCreator.SetMaterialIndex(0, 0);

multiPatchCreator.SetPatchPointIndex(0, 0);

multiPatchCreator.SetPatchTexturePointIndex(0, 0);

//Set real-world points.

WKSPointZ upperLeft = new WKSPointZ();

WKSPointZ lowerLeft = new WKSPointZ();

WKSPointZ upperRight = new WKSPointZ();

WKSPointZ lowerRight = new WKSPointZ();

upperLeft.X = 0;

upperLeft.Y = 0;

upperLeft.Z = 0;

upperRight.X = 300;

upperRight.Y = 0;

upperRight.Z = 0;

lowerLeft.X = 0;

lowerLeft.Y = 0;

lowerLeft.Z = -100;

lowerRight.X = 300;

lowerRight.Y = 1;

lowerRight.Z = -100;

multiPatchCreator.SetWKSPointZ(0, ref upperRight);

multiPatchCreator.SetWKSPointZ(1, ref lowerRight);

multiPatchCreator.SetWKSPointZ(2, ref upperLeft);

multiPatchCreator.SetWKSPointZ(3, ref lowerLeft);

//Set texture points.

//Set the texture coordinates for a panel.

WKSPoint textureUpperLeft = new WKSPoint();

WKSPoint textureLowerLeft = new WKSPoint();

WKSPoint textureUpperRight = new WKSPoint();

WKSPoint textureLowerRight = new WKSPoint();

textureUpperLeft.X = 0;

textureUpperLeft.Y = 0;

textureUpperRight.X = 1;

textureUpperRight.Y = 0;

textureLowerLeft.X = 0;

textureLowerLeft.Y = 1;

textureLowerRight.X = 1;

textureLowerRight.Y = 1;

multiPatchCreator.SetTextureWKSPoint(0, ref textureUpperRight);

multiPatchCreator.SetTextureWKSPoint(1, ref textureLowerRight);

multiPatchCreator.SetTextureWKSPoint(2, ref textureUpperLeft);

multiPatchCreator.SetTextureWKSPoint(3, ref textureLowerLeft);

IMultiPatch multiPatch = multiPatchCreator.CreateMultiPatch() as IMultiPatch;

return multiPatch;

}