angine有没办法计算面积

刚开始学习angine,做了点东西,都是抄这抄那,这个计算面的面积或者是线的长度等,好像找不到,希望大侠可以指点一下,最好能奉献出源码,感激!!

xiexie,i love you

xiexie

<img src="images/post/smile/dvbbs/em01.gif" /><img src="images/post/smile/dvbbs/em02.gif" /><img src="images/post/smile/dvbbs/em05.gif" /><img src="images/post/smile/dvbbs/em07.gif" /><img src="images/post/smile/dvbbs/em08.gif" />

<img src="images/post/smile/dvbbs/em01.gif" />好同志。<img src="images/post/smile/dvbbs/em08.gif" />

<P>已经调试成功!刚脆把代码贴出来一起分享.</P>
<P>Public Sub SelectMouseDown(x As Long, y As Long)<BR>  Dim pFeatureLayer As IFeatureLayer<BR>  Dim pFeatureClass As IFeatureClass<BR>  Dim pSpatialFilter As ISpatialFilter<BR>  Dim pFilter As IQueryFilter<BR>  Dim pActiveView As IActiveView<BR>  Dim pGeometry As IGeometry<BR>  Dim pPoint As IPoint<BR>  <BR>  <BR>  <BR>  On Error GoTo SelectMouseDown_err<BR>  <BR>  If m_pCurrentLayer Is Nothing Then Exit Sub<BR>  If Not TypeOf m_pCurrentLayer Is IGeoFeatureLayer Then Exit Sub<BR>  <BR>  ' Get the feature layer and class of the current layer<BR>  Set pFeatureLayer = m_pCurrentLayer<BR>  Set pFeatureClass = pFeatureLayer.FeatureClass<BR>   <BR>  If pFeatureClass Is Nothing Then Exit Sub<BR>  <BR>  ' Get the mouse down position in map coordinates<BR>  Set pActiveView = m_pMap<BR>  Set pPoint = pActiveView.ScreenDisplay.DisplayTransformation.ToMapPoint(x, y)<BR>  Set pGeometry = pPoint<BR>  <BR>  ' Use a four pixel buffer around the cursor for feature search<BR>  Dim length As Double<BR>  length = ConvertPixelsToMapUnits(m_pMap, 4)<BR>  Dim pTopo As ITopologicalOperator<BR>  Set pTopo = pGeometry<BR>  Dim pBuffer As IGeometry<BR>  Set pBuffer = pTopo.Buffer(length)<BR>  Set pGeometry = pBuffer.Envelope<BR>  <BR>  ' Set up a Filter specific to this layer<BR>  Set pSpatialFilter = New SpatialFilter<BR>  Set pSpatialFilter.Geometry = pGeometry<BR>  Select Case pFeatureClass.ShapeType<BR>    Case esriGeometryPoint<BR>      pSpatialFilter.SpatialRel = esriSpatialRelContains<BR>    Case esriGeometryPolyline<BR>      pSpatialFilter.SpatialRel = esriSpatialRelCrosses<BR>    Case esriGeometryPolygon<BR>      pSpatialFilter.SpatialRel = esriSpatialRelIntersects<BR>      <BR>  End Select<BR>  pSpatialFilter.GeometryField = pFeatureClass.ShapeFieldName<BR>  Set pFilter = pSpatialFilter<BR> <BR>  ' Do the search<BR>  Dim pCursor As IFeatureCursor<BR>  Set pCursor = pFeatureLayer.Search(pFilter, False)<BR>  <BR>  ' and select the features on the map<BR>  Dim pFeature As iFeature<BR>  Set pFeature = pCursor.NextFeature<BR>  <BR>  Dim pArea As IArea '面积<BR>  Dim pCurve As ICurve '周长<BR>  Dim pCenter As IPoint<BR>  Dim pLabel As IPoint<BR>  Dim Pstr As String<BR>  Set pCenter = New Point<BR>  Set pLabel = New Point<BR>  <BR>  <BR>  <BR>  While Not pFeature Is Nothing<BR>    Select Case pFeature.Shape.GeometryType    '计算面积<BR>    Case esriGeometryPolygon<BR>      Set pArea = pFeature.Shape<BR>      Set pCurve = pFeature.Shape<BR>      Pstr = "长度:" + CStr(Abs(Round(pCurve.length, 3))) + " 面积:" + CStr(Abs(Round(pArea.Area, 3)))<BR>    Case esriGeometryPolyline<BR>      Set pCurve = pFeature.Shape<BR>      Pstr = "长度:" + CStr(Abs(Round(pCurve.length, 3)))<BR>    Case Else<BR>      Pstr = ""<BR>    End Select<BR>    <BR>    m_pMap.SelectFeature m_pCurrentLayer, pFeature<BR>    Set pFeature = pCursor.NextFeature<BR>  Wend<BR>  pActiveView.PartialRefresh esriViewGeoSelection, Nothing, Nothing<BR>   <BR>  frmMain.StatusBar1.Panels(2).Text = Pstr<BR>  <BR>  ClearSelect<BR>  Exit Sub<BR>SelectMouseDown_err:<BR>  MsgBox Err.Description<BR>End Sub</P>
<img src="images/post/smile/dvbbs/em04.gif" />

area函数还要注意正负

多谢大侠!

<P>.length</P>
<P>.area</P>
<P>在帮助里查看下</P>