本文共 4168 字，大约阅读时间需要 13 分钟。

创建ArcGIS工作空间和处理地理数据的完整流程

1. 创建ArcGIS工作空间工厂——EDN

在编写代码时，首先需要创建工作空间工厂以管理数据源。以下代码示例展示了如何使用AccessWorkspaceFactory来创建一个新的工作空间。

public void IWorkspaceFactory_Create_Example_Access()  
{  
    IWorkspaceFactory workspaceFactory = new ESRI.ArcGIS.DataSourcesGDB.AccessWorkspaceFactoryClass();  
    IWorkspaceName workspaceName = workspaceFactory.Create("C:\\temp\\", "MyNewpGDB.mdb", null, 0);  
    IWorkspace pGDB_workspace = (IWorkspace)workspaceName.Open();  
    Console.WriteLine("Current path of the {0} is {1}", pGDB_workspace.Type, pGDB_workspace.PathName);  
}

2. 遍历所有图层

知道如何高效地遍历地图中的所有图层是 GIS 开发中的常见任务。以下方法展示了如何通过枚举层来筛选特定类型的UID。

IMap pMap = axMapControl1.Map;  
IEnumLayer pEnumLayer = pMap.get_Layers(null, true);  
pEnumLayer.Reset();  
ILayer pLayer = pEnumLayer.Next();  
while (pLayer != null)  
{  
    pLayer = pEnumLayer.Next();  
}

3. 判断图层类型

在ArcGIS中，判断图层类型有助于定制操作。以下代码可以根据图层的GUID确定其类型。

public I3DProperties get3DProps(IFeatureLayer pFeatLayer)  
{  
    I3DProperties p3DProps = null;  
    ILayer pLayer = pFeatLayer as ILayer;  
    ILayerExtensions lyrExt = pLayer as ILayerExtensions;  
    for (int i = 0; i < lyrExt.ExtensionCount; i++)  
    {  
        if (lyrExt.get_Extension(i) is I3DProperties)  
        {  
            p3DProps = lyrExt.get_Extension(i) as I3DProperties;  
        }  
    }  
    return p3DProps;  
}

4. 基于图层名称获取当前图层

有时，根据图层名称找到特定图层是必要的。以下代码实现了两种方法：通过名称匹配和通过选中元素获取。

Private Function GetCurLayer() As ILayer  
    Dim i As Integer  
    Set GetCurLayer = Nothing  
    For i = 0 To ff_m_Map.LayerCount - 1  
        If UCase$(ff_m_Map.Layer(i).Name) = UCase$(ff_m_strCurLayername) Then  
            Set GetCurLayer = ff_m_Map.Layer(i)  
            Exit For  
        End If  
        Next i  
End Function

5. 打开TIN数据集

处理TIN数据集需要使用专门的接口。以下代码展示了如何打开并访问TIN数据集。

public ILayer openTinLayer(string fullPath)  
{  
    ITinWorkspace pTinWorkspace;  
    IWorkspace pWS;  
    IWorkspaceFactory pWSFact = new TinWorkspaceFactoryClass();  
    string pathToWorkspace = System.IO.Path.GetDirectoryName(fullPath);  
    string tinName = System.IO.Path.GetFileName(fullPath);  
    pWS = pWSFact.OpenFromFile(pathToWorkspace, 0);  
    ITinWorkspace pTinWorkspace = pWS as ITinWorkspace;  
    if (pTinWorkspace.get_IsTin(tinName))  
    {  
        ITin pTin = pTinWorkspace.OpenTin(tinName);  
        pTinLayer.Dataset = pTin;  
        pTinLayer.ClearRenderers();  
        return pTinLayer as ILayer;  
    }  
    else  
    {  
        MessageBox.Show("该目录不包含Tin文件");  
        return null;  
    }  
}

6. 构建IPolyline或IPolygon

将点集合转换为线或面是 GIS 开发中的常见操作。以下代码展示了如何创建并添加点到IPolyline或IPolygon中。

IPolyline m_ProfilePolyline = new PolylineClass();  
IPointCollection m_PtCol = m_ProfilePolyline as IPointCollection;  
IPoint pPoint1 = new PointClass();  
pPoint1.X = x; pPoint1.Y = y; m_PtCol.AddPoint(pPoint1, ref missing, ref missing);  
IPoint pPoint2 = new PointClass();  
pPoint2.X = x; pPoint2.Y = y; m_PtCol.AddPoint(pPoint2, ref missing, ref missing);

7. 平缓处理（Buffering）

在ArcGIS中，平缓处理是构造缓冲区的一种常用操作。以下代码展示了如何将线向两侧平移以构造矩形或面。

private IPolygon FlatBuffer(IPolyline myLine, double bufferDis)  
{  
    object o = System.Type.Missing;  
    IConstructCurve mycurve = new PolylineClass();  
    mycurve.ConstructOffset(myLine, bufferDis, ref o, ref o);  
    IPointCollection pCol = mycurve as IPointCollection;  
    IConstructCurve mycurve2 = new PolylineClass();  
    mycurve2.ConstructOffset(myLine, -1 * bufferDis, ref o, ref o);  
    IPolyline addline = mycurve2 as IPolyline;  
    addline.ReverseOrientation();  
    IPointCollection pCol2 = addline as IPointCollection;  
    IPointCollection myPCol = new PolygonClass();  
    myPCol.AddPointCollection(pCol);  
    IPolygon myPolygon = myPCol as IPolygon;  
    myPolygon.SimplifyPreserveFromTo();  
    return myPolygon;  
}

8. 遍历要素类中的所有字段

获取要素类中的所有字段是开发过程中常需操作。以下代码展示了如何筛选非几何字段并添加到控件中。

IField pField = null;  
IFields pFields = pFeatureClass.Fields;  
for (int i = 0; i < pFields.FieldCount - 1; i++)  
{  
    pField = pFields.get_Field(i);  
    if (pField.Type != esriFieldType.esriFieldTypeGeometry)  
    {  
        dgvCombo.Items.Add(pField.Name);  
    }  
}

参考文献

• ArcGIS API 参考
• GIS 开发教程

转载地址：http://mdayk.baihongyu.com/