佩服.佩服.译得太好了.我现在才发现以自己怎么没有来这么一个好地方.现在好了.我以后一定经常来.!

感谢，疑惑很久没有这样清晰对口的回答了，感谢！

<P>请问一下  如何选择中央子午线呢  还想问一下上面提到的地理坐标系统是采用了3度带还是6度带呢?</P>

<P 0cm 0cm 0pt; TEXT-ALIGN: left; mso-layout-grid-align: none" align=left><STRONG><FONT face=Verdana color=#61b713>回whuyp的问题</FONT></STRONG></P>
<P 0cm 0cm 0pt; TEXT-ALIGN: left; mso-layout-grid-align: none" align=left>高斯<B><FONT face="Times New Roman">—</FONT></B>克吕格投影<p></p></P>
<P 0cm 0cm 0pt; TEXT-ALIGN: left; mso-layout-grid-align: none" align=left>是采用分带办法控制地图的变形。也是常用的投影方式。<p></p></P>
<P 0cm 0cm 0pt; TEXT-ALIGN: left; mso-layout-grid-align: none" align=left>我国<FONT face="Times New Roman">1/2.5 </FONT>万<FONT face="Times New Roman">—1/50 </FONT>万地图采用<FONT face="Times New Roman">6 </FONT>度分带，<FONT face="Times New Roman">1/</FONT>万地图采用<FONT face="Times New Roman">3 </FONT>度分带。<p></p></P>
<P 0cm 0cm 0pt; TEXT-ALIGN: left; mso-layout-grid-align: none" align=left>具体每个带的投影中央经度见参考书。<p></p></P>
<P 0cm 0cm 0pt; TEXT-ALIGN: left; mso-layout-grid-align: none" align=left>我省跨两个投影<FONT face="Times New Roman">6 </FONT>度带。分别是<FONT face="Times New Roman">111 </FONT>和<FONT face="Times New Roman">117</FONT>。<p></p></P>
<P 0cm 0cm 0pt; TEXT-ALIGN: left; mso-layout-grid-align: none" align=left>在京广线以西的地区<FONT face="Times New Roman">,108 </FONT>度—<FONT face="Times New Roman">114 </FONT>度之间的投影中央经线是<FONT face="Times New Roman">111 </FONT>度。<p></p></P>
<P 0cm 0cm 0pt; TEXT-ALIGN: left; mso-layout-grid-align: none" align=left><FONT face="Times New Roman">114-120 </FONT>度之间的投影中央经线是<FONT face="Times New Roman">117 </FONT>度。<p></p></P>
<P 0cm 0cm 0pt; TEXT-ALIGN: left; mso-layout-grid-align: none" align=left>根据图上大地坐标注判断中央经线：<p></p></P>
<P 0cm 0cm 0pt; TEXT-ALIGN: left; mso-layout-grid-align: none" align=left><FONT face="Times New Roman">6 </FONT>度带：中央经线<FONT face="Times New Roman">=</FONT>带号<FONT face="Times New Roman">*6-3</FONT>， <FONT face="Times New Roman">3 </FONT>度带：中央经线<FONT face="Times New Roman">=</FONT>带号<FONT face="Times New Roman">*3<p></p></FONT></P>
<P 0cm 0cm 0pt; TEXT-ALIGN: left; mso-layout-grid-align: none" align=left><FONT face="Times New Roman">ZZHZJ </FONT>为云飞软件园论坛<FONT face="Times New Roman">-</FONT>地理信息系统块而做 <FONT face="Times New Roman">http://www.chinalotus.com/wyf/forumdisplay.php?fid=32<p></p></FONT></P>
<P 0cm 0cm 0pt; TEXT-ALIGN: left; mso-layout-grid-align: none" align=left><FONT face="Times New Roman">2<p></p></FONT></P>
<P 0cm 0cm 0pt; TEXT-ALIGN: left; mso-layout-grid-align: none" align=left>如：<FONT face="Times New Roman">19340000</FONT>，前面两位数<FONT face="Times New Roman">19 </FONT>是带号，且表示<FONT face="Times New Roman">6 </FONT>度带，此时该幅图的中央经线<p></p></P>
<P 0cm 0cm 0pt; TEXT-ALIGN: left; mso-layout-grid-align: none" align=left>是<FONT face="Times New Roman">19*6-3=111 </FONT>度。<p></p></P>
<P 0cm 0cm 0pt; TEXT-ALIGN: left; mso-layout-grid-align: none" align=left>又如：<FONT face="Times New Roman">38340000</FONT>，前两位<FONT face="Times New Roman">38 </FONT>是带号，表示<FONT face="Times New Roman">3 </FONT>度带，则其中央经线是：<FONT face="Times New Roman">38*3=114<p></p></FONT></P>
<P 0cm 0cm 0pt; TEXT-ALIGN: left; mso-layout-grid-align: none" align=left>度。<p></p></P>

<P>太受益了</P><img src="images/post/smile/dvbbs/em03.gif" />

<P>哪位高手能用代码写一下，获取</P>
<P>像这样</P>
<P>Projection: Gauss_Kruger<BR>False_Easting: 500000.000000<BR>False_Northing: 0.000000<BR>Central_Meridian: 120.000000<BR>Scale_Factor: 1.000000<BR>Latitude_Of_Origin: 0.000000<BR>Linear Unit: Meter (1.000000)</P>
<P>Geographic Coordinate System: GCS_Xian_1980<BR>Angular Unit: Degree (0.017453292519943299)<BR>Prime Meridian: Greenwich (0.000000000000000000)<BR>Datum: D_Xian_1980<BR>  Spheroid: IUGG_1975<BR>    Semimajor Axis: 6378140.000000000000000000<BR>    Semiminor Axis: 6356755.288157528300000000<BR>    Inverse Flattening: 298.257000000000010000<BR><BR>的。</P>
<P>？？先谢了</P>

<P>终于探索出来了，哈。。</P>

<P>谢谢,终于搞懂了!</P><img src="images/post/smile/dvbbs/em01.gif" /><img src="images/post/smile/dvbbs/em02.gif" /><img src="images/post/smile/dvbbs/em06.gif" />

<img src="images/post/smile/dvbbs/em04.gif" />

<P>谢谢啊，正好需要</P>