mapobject学习笔记－第六讲 mo中的坐标和坐标系_魏国强 的 博客.htm

MO+VC的学习文档资料

      style="MARGIN: 0cm 0cm 0pt; TEXT-INDENT: 21.75pt"><SPAN>Dim dc As New 
      DataConnection</SPAN></P>
      <P class=MsoNormal 
      style="MARGIN: 0cm 0cm 0pt; TEXT-INDENT: 21.75pt"><SPAN>Dim layer As 
      MapObjects2.MapLayer</SPAN></P>
      <P class=MsoNormal style="MARGIN: 0cm 0cm 0pt; TEXT-INDENT: 21.75pt"></P>
      <P class=MsoNormal 
      style="MARGIN: 0cm 0cm 0pt; TEXT-INDENT: 21.75pt"><SPAN>Private Sub 
      Command1_Click()</SPAN></P>
      <P class=MsoNormal 
      style="MARGIN: 0cm 0cm 0pt; TEXT-INDENT: 21.75pt"><SPAN>Dim csmap As New 
      MapObjects2.ProjCoordSys</SPAN></P>
      <P class=MsoNormal style="MARGIN: 0cm 0cm 0pt; TEXT-INDENT: 21.75pt"></P>
      <P class=MsoNormal 
      style="MARGIN: 0cm 0cm 0pt; TEXT-INDENT: 21.75pt"><SPAN>'Map1.Layers(0).CoordinateSystem 
      = Map1.Layers(1).CoordinateSystem</SPAN></P>
      <P class=MsoNormal 
      style="MARGIN: 0cm 0cm 0pt; TEXT-INDENT: 21.75pt"><SPAN>csmap.Type = 
      moProjCS_World_WinkelI</SPAN></P>
      <P class=MsoNormal 
      style="MARGIN: 0cm 0cm 0pt; TEXT-INDENT: 21.75pt"><SPAN>Map1.CoordinateSystem 
      = csmap</SPAN></P>
      <P class=MsoNormal 
      style="MARGIN: 0cm 0cm 0pt; TEXT-INDENT: 21.75pt"><SPAN>End Sub</SPAN></P>
      <P class=MsoNormal style="MARGIN: 0cm 0cm 0pt; TEXT-INDENT: 21.75pt"></P>
      <P class=MsoNormal 
      style="MARGIN: 0cm 0cm 0pt; TEXT-INDENT: 21.75pt"><SPAN>Private Sub 
      Command2_Click()</SPAN></P>
      <P class=MsoNormal 
      style="MARGIN: 0cm 0cm 0pt; TEXT-INDENT: 21.75pt"><SPAN>Map1.CoordinateSystem 
      = Map1.Layers(1).CoordinateSystem.Type</SPAN></P>
      <P class=MsoNormal 
      style="MARGIN: 0cm 0cm 0pt; TEXT-INDENT: 21.75pt"><SPAN>End Sub</SPAN></P>
      <P class=MsoNormal style="MARGIN: 0cm 0cm 0pt; TEXT-INDENT: 21.75pt"></P>
      <P class=MsoNormal 
      style="MARGIN: 0cm 0cm 0pt; TEXT-INDENT: 21.75pt"><SPAN>Private Sub 
      Form_Load()</SPAN></P>
      <P class=MsoNormal 
      style="MARGIN: 0cm 0cm 0pt; TEXT-INDENT: 21.75pt"><SPAN>Command1.Caption = 
      "</SPAN><SPAN>投影坐标系</SPAN><SPAN>"</SPAN></P>
      <P class=MsoNormal 
      style="MARGIN: 0cm 0cm 0pt; TEXT-INDENT: 21.75pt"><SPAN>Command2.Caption = 
      "</SPAN><SPAN>地理坐标系</SPAN><SPAN>"</SPAN></P>
      <P class=MsoNormal 
      style="MARGIN: 0cm 0cm 0pt; TEXT-INDENT: 21.75pt"><SPAN>layset</SPAN></P>
      <P class=MsoNormal 
      style="MARGIN: 0cm 0cm 0pt; TEXT-INDENT: 21.75pt"><SPAN>End Sub</SPAN></P>
      <P class=MsoNormal 
      style="MARGIN: 0cm 0cm 0pt; TEXT-INDENT: 21.75pt"><SPAN>Private Sub 
      layset()</SPAN></P>
      <P class=MsoNormal 
      style="MARGIN: 0cm 0cm 0pt; TEXT-INDENT: 21.75pt"><SPAN>dc.Database = 
      App.Path + "\..\" + "world"</SPAN></P>
      <P class=MsoNormal 
      style="MARGIN: 0cm 0cm 0pt; TEXT-INDENT: 21.75pt"><SPAN>Set layer = New 
      MapLayer</SPAN></P>
      <P class=MsoNormal 
      style="MARGIN: 0cm 0cm 0pt; TEXT-INDENT: 21.75pt"><SPAN>Set 
      layer.GeoDataset = dc.FindGeoDataset("country")</SPAN></P>
      <P class=MsoNormal 
      style="MARGIN: 0cm 0cm 0pt; TEXT-INDENT: 21.75pt"><SPAN>layer.Symbol.Color 
      = moBlue</SPAN></P>
      <P class=MsoNormal 
      style="MARGIN: 0cm 0cm 0pt; TEXT-INDENT: 21.75pt"><SPAN>Map1.Layers.Add 
      layer</SPAN></P>
      <P class=MsoNormal 
      style="MARGIN: 0cm 0cm 0pt; TEXT-INDENT: 21.75pt"><SPAN>Set layer = New 
      MapLayer</SPAN></P>
      <P class=MsoNormal 
      style="MARGIN: 0cm 0cm 0pt; TEXT-INDENT: 21.75pt"><SPAN>Set 
      layer.GeoDataset = dc.FindGeoDataset("latlong")</SPAN></P>
      <P class=MsoNormal 
      style="MARGIN: 0cm 0cm 0pt; TEXT-INDENT: 21.75pt"><SPAN>layer.Symbol.Color 
      = moBlack</SPAN></P>
      <P class=MsoNormal 
      style="MARGIN: 0cm 0cm 0pt; TEXT-INDENT: 21.75pt"><SPAN>layer.Symbol.Size 
      = 1</SPAN></P>
      <P class=MsoNormal 
      style="MARGIN: 0cm 0cm 0pt; TEXT-INDENT: 21.75pt"><SPAN>Map1.Layers.Add 
      layer</SPAN></P>
      <P class=MsoNormal 
      style="MARGIN: 0cm 0cm 0pt; TEXT-INDENT: 21.75pt"><SPAN>Map1.Refresh</SPAN></P>
      <P class=MsoNormal 
      style="MARGIN: 0cm 0cm 0pt; TEXT-INDENT: 21.75pt"><SPAN>End 
      Sub</SPAN></P><SPAN>
      <P class=MsoNormal 
      style="MARGIN: 0cm 0cm 0pt; TEXT-INDENT: 21.75pt"><STRONG><SPAN 
      style="FONT-SIZE: 12pt">二、地图上坐标单位及其转换</SPAN></STRONG></P>
      <P class=MsoNormal 
      style="MARGIN: 0cm 0cm 0pt; TEXT-INDENT: 21.75pt"><STRONG><SPAN>1</SPAN></STRONG><STRONG><SPAN>、在地图上显示经纬度</SPAN></STRONG></P>
      <P class=MsoNormal 
      style="MARGIN: 0cm 0cm 0pt; TEXT-INDENT: 21.75pt"><SPAN>点击地图查看坐标时，如果不作任何的坐标转换，在</SPAN><SPAN>Map1_MouseDown</SPAN><SPAN>过程中</SPAN><SPAN>X</SPAN><SPAN>和</SPAN><SPAN>Y</SPAN><SPAN>的显示坐标为控件的原始坐标（</SPAN><SPAN>twips</SPAN><SPAN>）。用</SPAN><SPAN>ToMapDsitance</SPAN><SPAN>和</SPAN><SPAN>ToMapPoint</SPAN><SPAN>方法，可以把点击坐标转换成地图坐标。</SPAN></P>
      <P class=MsoNormal style="MARGIN: 0cm 0cm 0pt; TEXT-INDENT: 21.75pt"><SPAN 
      style="COLOR: red">ToMapDsitance</SPAN><SPAN 
      style="COLOR: red">是地图控件的成员函数之一，其功能是将屏幕坐标的距离值转换为地图坐标系的距离值，语法为</SPAN><SPAN 
      style="COLOR: red">object.ToMapDistance distance</SPAN><SPAN 
      style="COLOR: red">，返回值是地图坐标系的距离值，</SPAN><SPAN 
      style="COLOR: red">distance</SPAN><SPAN 
      style="COLOR: red">为屏幕坐标的距离值。</SPAN></P>
      <P class=MsoNormal 
      style="MARGIN: 0cm 0cm 0pt; TEXT-INDENT: 21.75pt"><SPAN>下面程序是将世界地图进行图上坐标向经纬度转换的示例，用</SPAN><SPAN>ToMapDsitance</SPAN><SPAN>方法时，地图从左到右为</SPAN><SPAN>0</SPAN><SPAN>－</SPAN><SPAN>360</SPAN><SPAN>度，从上到下为</SPAN><SPAN>0</SPAN><SPAN>－</SPAN><SPAN>180</SPAN><SPAN>度。用</SPAN><SPAN>ToMapPoint</SPAN><SPAN>方法时，考虑了</SPAN><SPAN>Datum</SPAN><SPAN>和</SPAN><SPAN>PrimeMeridian</SPAN><SPAN>属性，从伦敦开始向右为正（</SPAN><SPAN>0</SPAN><SPAN>－</SPAN><SPAN>180</SPAN><SPAN>），向左为负（</SPAN><SPAN>-180</SPAN><SPAN>－</SPAN><SPAN>0</SPAN><SPAN>），从赤道向上为</SPAN><SPAN>0</SPAN><SPAN>－</SPAN><SPAN>90</SPAN><SPAN>，向下为</SPAN><SPAN>-90</SPAN><SPAN>－</SPAN><SPAN>0</SPAN><SPAN>。代码如下：</SPAN></P>
      <P class=MsoNormal 
      style="MARGIN: 0cm 0cm 0pt; TEXT-INDENT: 21.75pt"><SPAN>Dim dc As New 
      DataConnection</SPAN></P>
      <P class=MsoNormal 
      style="MARGIN: 0cm 0cm 0pt; TEXT-INDENT: 21.75pt"><SPAN>Dim layer As 
      MapObjects2.MapLayer</SPAN></P>
      <P class=MsoNormal style="MARGIN: 0cm 0cm 0pt; TEXT-INDENT: 21.75pt"></P>
      <P class=MsoNormal 
      style="MARGIN: 0cm 0cm 0pt; TEXT-INDENT: 21.75pt"><SPAN>Private Sub 
      Command1_Click()</SPAN></P>
      <P class=MsoNormal 
      style="MARGIN: 0cm 0cm 0pt; TEXT-INDENT: 21.75pt"><SPAN>Dim mapGCS As New 
      MapObjects2.GeoCoordSys</SPAN></P>
      <P class=MsoNormal 
      style="MARGIN: 0cm 0cm 0pt; TEXT-INDENT: 21.75pt"><SPAN>mapGCS.Type = 
      Map1.Layers(1).CoordinateSystem.Type</SPAN></P>
      <P class=MsoNormal 
      style="MARGIN: 0cm 0cm 0pt; TEXT-INDENT: 21.75pt"><SPAN>MsgBox "datum = " 
      &amp; mapGCS.Datum.Name &amp; " ,primemridian= " &amp; 
      mapGCS.PrimeMeridian.Name</SPAN></P>
      <P class=MsoNormal style="MARGIN: 0cm 0cm 0pt; TEXT-INDENT: 21.75pt"></P>
      <P class=MsoNormal 
      style="MARGIN: 0cm 0cm 0pt; TEXT-INDENT: 21.75pt"><SPAN>End Sub</SPAN></P>
      <P class=MsoNormal style="MARGIN: 0cm 0cm 0pt; TEXT-INDENT: 21.75pt"></P>
      <P class=MsoNormal 
      style="MARGIN: 0cm 0cm 0pt; TEXT-INDENT: 21.75pt"><SPAN>Private Sub 
      Form_Load()</SPAN></P>
      <P class=MsoNormal 
      style="MARGIN: 0cm 0cm 0pt; TEXT-INDENT: 21.75pt"><SPAN>Label1.Caption = 
      "</SPAN><SPAN>点击地图显示经纬度</SPAN><SPAN>"</SPAN></P>
      <P class=MsoNormal 
      style="MARGIN: 0cm 0cm 0pt; TEXT-INDENT: 21.75pt"><SPAN>layset</SPAN></P>
      <P class=MsoNormal 
      style="MARGIN: 0cm 0cm 0pt; TEXT-INDENT: 21.75pt"><SPAN>Command1.Caption = 
      "</SPAN><SPAN>显示坐标信息</SPAN><SPAN>"</SPAN></P>
      <P class=MsoNormal 
      style="MARGIN: 0cm 0cm 0pt; TEXT-INDENT: 21.75pt"><SPAN>Option1.Caption = 
      "ToMapDsitance"</SPAN></P>
      <P class=MsoNormal 
      style="MARGIN: 0cm 0cm 0pt; TEXT-INDENT: 21.75pt"><SPAN>Option2.Caption = 
      "ToMapPoint"</SPAN></P>
      <P class=MsoNormal 
      style="MARGIN: 0cm 0cm 0pt; TEXT-INDENT: 21.75pt"><SPAN>End Sub</SPAN></P>
      <P class=MsoNormal 
      style="MARGIN: 0cm 0cm 0pt; TEXT-INDENT: 21.75pt"><SPAN>Private Sub 
      layset()</SPAN></P>
      <P class=MsoNormal 
      style="MARGIN: 0cm 0cm 0pt; TEXT-INDENT: 21.75pt"><SPAN>dc.Database = 
      App.Path + "\..\" + "world"</SPAN></P>
      <P class=MsoNormal 
      style="MARGIN: 0cm 0cm 0pt; TEXT-INDENT: 21.75pt"><SPAN>Set layer = New 
      MapLayer</SPAN></P>
      <P class=MsoNormal 
      style="MARGIN: 0cm 0cm 0pt; TEXT-INDENT: 21.75pt"><SPAN>Set 
      layer.GeoDataset = dc.FindGeoDataset("country")</SPAN></P>
      <P class=MsoNormal 
      style="MARGIN: 0cm 0cm 0pt; TEXT-INDENT: 21.75pt"><SPAN>layer.Symbol.Color 
      = moBlue</SPAN></P>
      <P class=MsoNormal 
      style="MARGIN: 0cm 0cm 0pt; TEXT-INDENT: 21.75pt"><SPAN>Map1.Layers.Add 
      layer</SPAN></P>
      <P class=MsoNormal 
      style="MARGIN: 0cm 0cm 0pt; TEXT-INDENT: 21.75pt"><SPAN>Set layer = New 
      MapLayer</SPAN></P>
      <P class=MsoNormal 
      style="MARGIN: 0cm 0cm 0pt; TEXT-INDENT: 21.75pt"><SPAN>Set 
      layer.GeoDataset = dc.FindGeoDataset("latlong")</SPAN></P>
      <P class=MsoNormal 
      style="MARGIN: 0cm 0cm 0pt; TEXT-INDENT: 21.75pt"><SPAN>layer.Symbol.Color 
      = moBlack</SPAN></P>
      <P class=MsoNormal 
      style="MARGIN: 0cm 0cm 0pt; TEXT-INDENT: 21.75pt"><SPAN>layer.Symbol.Size 
      = 1</SPAN></P>
      <P class=MsoNormal 
      style="MARGIN: 0cm 0cm 0pt; TEXT-INDENT: 21.75pt"><SPAN>Map1.Layers.Add 
      layer</SPAN></P>
      <P class=MsoNormal 
      style="MARGIN: 0cm 0cm 0pt; TEXT-INDENT: 21.75pt"><SPAN>Map1.Refresh</SPAN></P>
      <P class=MsoNormal 
      style="MARGIN: 0cm 0cm 0pt; TEXT-INDENT: 21.75pt"><SPAN>End 
      Sub</SPAN></P><SPAN>
      <P class=MsoNormal 
      style="MARGIN: 0cm 0cm 0pt; TEXT-INDENT: 21.75pt"><SPAN>Private Sub 
      Map1_MouseDown(Button As Integer, Shift As Integer, X As Single, Y As 
      Single)</SPAN></P>
      <P class=MsoNormal 
      style="MARGIN: 0cm 0cm 0pt; TEXT-INDENT: 21.75pt"><SPAN>Dim str1 As 
      String</SPAN></P>
      <P class=MsoNormal 
      style="MARGIN: 0cm 0cm 0pt; TEXT-INDENT: 21.75pt"><SPAN>Dim p1 As 
      MapObjects2.Point</SPAN></P>
      <P class=MsoNormal 
      style="MARGIN: 0cm 0cm 0pt; TEXT-INDENT: 21.75pt"><SPAN>If Not Option1 
      Then</SPAN></P>
      <P class=MsoNormal 
      style="MARGIN: 0cm 0cm 0pt; TEXT-INDENT: 21.75pt"><SPAN>Set p1 = 
      Map1.ToMapPoint(X, Y)</SPAN></P>
      <P class=MsoNormal 
      style="MARGIN: 0cm 0cm 0pt; TEXT-INDENT: 21.75pt"><SPAN>str1 = "x=" &amp; 
      Format(p1.X, "0.000") &amp; ",y=" &amp; Format(p1.Y, "0.000")</SPAN></P>
      <P class=MsoNormal 
      style="MARGIN: 0cm 0cm 0pt; TEXT-INDENT: 21.75pt"><SPAN>Else</SPAN></P>
      <P class=MsoNormal 
      style="MARGIN: 0cm 0cm 0pt; TEXT-INDENT: 21.75pt"><SPAN>str1 = "x=" &amp; 
      Format(Map1.ToMapDistance(X), "0.000") &amp; ",y=" &amp; 
      Format(Map1.ToMapDistance(Y), "0.000")</SPAN></P>
      <P class=MsoNormal 
      style="MARGIN: 0cm 0cm 0pt; TEXT-INDENT: 21.75pt"><SPAN>End If</SPAN></P>
      <P class=MsoNormal 
      style="MARGIN: 0cm 0cm 0pt; TEXT-INDENT: 21.75pt"><SPAN>Label1.Caption = 
      str1</SPAN></P>
      <P class=MsoNormal 
      style="MARGIN: 0cm 0cm 0pt; TEXT-INDENT: 21.75pt"><SPAN>Dim rec As 
      MapObjects2.Rectangle</SPAN></P>
      <P class=MsoNormal 
      style="MARGIN: 0cm 0cm 0pt; TEXT-INDENT: 21.75pt"><SPAN>If Button = 1 
      Then</SPAN></P>
      <P class=MsoNormal 
      style="MARGIN: 0cm 0cm 0pt; TEXT-INDENT: 21.75pt"><SPAN>Set Map1.Extent = 
      Map1.TrackRectangle</SPAN></P>
      <P class=MsoNormal 
      style="MARGIN: 0cm 0cm 0pt; TEXT-INDENT: 21.75pt"><SPAN>Else</SPAN></P>
      <P class=MsoNormal 
      style="MARGIN: 0cm 0cm 0pt; TEXT-INDENT: 21.75pt"><SPAN>Map1.Pan</SPAN></P>
      <P class=MsoNormal 
      style="MARGIN: 0cm 0cm 0pt; TEXT-INDENT: 21.75pt"><SPAN>Map1.Refresh</SPAN></P>
      <P class=MsoNormal 
      style="MARGIN: 0cm 0cm 0pt; TEXT-INDENT: 21.75pt"><SPAN>End If</SPAN></P>
      <P class=MsoNormal 
      style="MARGIN: 0cm 0cm 0pt; TEXT-INDENT: 21.75pt"><SPAN>End 
      Sub</SPAN></P><SPAN>
      <P class=MsoNormal 
      style="MARGIN: 0cm 0cm 0pt; TEXT-INDENT: 21.75pt"><STRONG><SPAN>2</SPAN></STRONG><STRONG><SPAN>、在地图上显示公里</SPAN><SPAN></SPAN></STRONG></P>
      <P class=MsoNormal 
      style="MARGIN: 0cm 0cm 0pt; TEXT-INDENT: 21.75pt"><SPAN>地球的赤道直径为</SPAN><ST1:CHMETCNV 
      unitname="km" sourcevalue="40075.7" hasspace="False" negative="False" 
      numbertype="1" 
      tcsc="0"><SPAN>40075.7km</SPAN></ST1:CHMETCNV><SPAN>，因此可以近视用</SPAN><SPAN>Dx=40075.7/360</SPAN><SPAN>表示度数向公里的转换系数。示例代码如下：</SPAN></P>
      <P class=MsoNormal 
      style="MARGIN: 0cm 0cm 0pt; TEXT-INDENT: 21.75pt"><SPAN>Dim dx As 
      Single</SPAN></P>
      <P class=MsoNormal 
      style="MARGIN: 0cm 0cm 0pt; TEXT-INDENT: 21.75pt"><SPAN>Dim dc As New 
      DataConnection</SPAN></P>
      <P class=MsoNormal 
      style="MARGIN: 0cm 0cm 0pt; TEXT-INDENT: 21.75pt"><SPAN>Dim layer As 
      MapObjects2.MapLayer</SPAN></P>
      <P class=MsoNormal 
      style="MARGIN: 0cm 0cm 0pt; TEXT-INDENT: 21.75pt"><SPAN></SPAN></P>
      <P class=MsoNormal 
      style="MARGIN: 0cm 0cm 0pt; TEXT-INDENT: 21.75pt"><SPAN>Private Sub 
      Form_Load()</SPAN></P>
      <P class=MsoNormal 
      style="MARGIN: 0cm 0cm 0pt; TEXT-INDENT: 21.75pt"><SPAN>dx = 40075.7 / 
      360</SPAN></P>
      <P class=MsoNormal 
      style="MARGIN: 0cm 0cm 0pt; TEXT-INDENT: 21.75pt"><SPAN>Label1.Caption = 
      "</SPAN><SPAN>点击地图显示公里</SPAN><SPAN>"</SPAN></P>
      <P class=MsoNormal 
      style="MARGIN: 0cm 0cm 0pt; TEXT-INDENT: 21.75pt"><SPAN>layset</SPAN></P>
      <P class=MsoNormal 
      style="MARGIN: 0cm 0cm 0pt; TEXT-INDENT: 21.75pt"><SPAN></SPAN></P>
      <P class=MsoNormal 
      style="MARGIN: 0cm 0cm 0pt; TEXT-INDENT: 21.75pt"><SPAN>End Sub</SPAN></P>
      <P class=MsoNormal 
      style="MARGIN: 0cm 0cm 0pt; TEXT-INDENT: 21.75pt"><SPAN>Private Sub 
      layset()</SPAN></P>
      <P class=MsoNormal 
      style="MARGIN: 0cm 0cm 0pt; TEXT-INDENT: 21.75pt"><SPAN>dc.Database = 
      App.Path + "\..\" + "world"</SPAN></P>
      <P class=MsoNormal 
      style="MARGIN: 0cm 0cm 0pt; TEXT-INDENT: 21.75pt"><SPAN>Set layer = New 
      MapLayer</SPAN></P>
      <P class=MsoNormal 
      style="MARGIN: 0cm 0cm 0pt; TEXT-INDENT: 21.75pt"><SPAN>Set 
      layer.GeoDataset = dc.FindGeoDataset("country")</SPAN></P>
      <P class=MsoNormal 
      style="MARGIN: 0cm 0cm 0pt; TEXT-INDENT: 21.75pt"><SPAN>layer.Symbol.Color 
      = moBlue</SPAN></P>
      <P class=MsoNormal 
      style="MARGIN: 0cm 0cm 0pt; TEXT-INDENT: 21.75pt"><SPAN>Map1.Layers.Add 
      layer</SPAN></P>
      <P class=MsoNormal 
      style="MARGIN: 0cm 0cm 0pt; TEXT-INDENT: 21.75pt"><SPAN>Set layer = New 
      MapLayer</SPAN></P>
      <P class=MsoNormal 
      style="MARGIN: 0cm 0cm 0pt; TEXT-INDENT: 21.75pt"><SPAN>Set 
      layer.GeoDataset = dc.FindGeoDataset("latlong")</SPAN></P>
      <P class=MsoNormal 
      style="MARGIN: 0cm 0cm 0pt; TEXT-INDENT: 21.75pt"><SPAN>layer.Symbol.Color 
      = moBlack</SPAN></P>
      <P class=MsoNormal 
      style="MARGIN: 0cm 0cm 0pt; TEXT-INDENT: 21.75pt"><SPAN>layer.Symbol.Size