[求助]航点坐标问题

<P >坐标转换问题</P>
<P ><p><FONT face="Times New Roman"> </FONT></p></P>
<P >以具体例子说明：</P>
<P ><p><FONT face="Times New Roman"> </FONT></p></P>
<P ><p><FONT face="Times New Roman"> </FONT></p></P>
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<P ><FONT face="Times New Roman">A</FONT>点</P></DIV></TD></TR></TABLE></v:textbox></v:shape><v:shape><v:textbox>
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<P ><FONT face="Times New Roman">B</FONT>点</P></DIV></TD></TR></TABLE></v:textbox></v:shape><v:shape><v:textbox>
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<P ><FONT face="Times New Roman">C</FONT>点</P></DIV></TD></TR></TABLE></v:textbox></v:shape></v:group><w:wrap type="none"></w:wrap><w:anchorlock></w:anchorlock></v:group></P>
<P ><p><FONT face="Times New Roman"> </FONT></p></P>
<P ><p><FONT face="Times New Roman"> </FONT></p></P>
<P ><FONT face="Times New Roman">A</FONT>点：起飞点<FONT face="Times New Roman"> </FONT>由用户输入的经纬度（准确的）</P>
<P >如何求得<FONT face="Times New Roman">B</FONT>、<FONT face="Times New Roman">C</FONT>点的经纬度坐标？</P>
<P ><p><FONT face="Times New Roman"> </FONT></p></P>
<P >我们是这样想的：通过转化<FONT face="Times New Roman"> </FONT>可以得到<FONT face="Times New Roman"> A</FONT>点的<FONT face="Times New Roman"> XY</FONT>值<FONT face="Times New Roman"> </FONT>（采用<FONT face="Times New Roman">6</FONT>度带）；<FONT face="Times New Roman">B</FONT>、<FONT face="Times New Roman">C</FONT>点是可以求解方程得到<FONT face="Times New Roman"> XY</FONT>值的<FONT face="Times New Roman"> </FONT>最后转化为<FONT face="Times New Roman">B</FONT>、<FONT face="Times New Roman">C</FONT>的经纬度。但是问题是：</P>
<P >采用<FONT face="Times New Roman">6</FONT>度带转化坐标需要一个中央子午线的参数（<FONT face="Times New Roman">L0</FONT>），<FONT face="Times New Roman">L0 </FONT>一般是<FONT face="Times New Roman"> </FONT>根据<FONT face="Times New Roman"> </FONT>某点的经度<FONT face="Times New Roman"> </FONT>求出的。如果上面航线都在某一个带的范围内，则没有问题，<FONT face="Times New Roman">B</FONT>、<FONT face="Times New Roman">C</FONT>点的经纬度精确很高的。</P>
<P ><p><FONT face="Times New Roman"> </FONT></p></P>
<P >可是飞机的航线很长，跨过<FONT face="Times New Roman">N</FONT>个带，</P>
<P >此时<FONT face="Times New Roman">B</FONT>、<FONT face="Times New Roman">C </FONT>的<FONT face="Times New Roman"> </FONT>位置和<FONT face="Times New Roman">A</FONT>点不在一个带内，所以<FONT face="Times New Roman">B</FONT>、<FONT face="Times New Roman">C</FONT>点的<FONT face="Times New Roman">L0 </FONT>和<FONT face="Times New Roman"> A</FONT>点的<FONT face="Times New Roman">L0</FONT>是不一样的</P>
<P >如果用<FONT face="Times New Roman">A</FONT>点的<FONT face="Times New Roman">L0</FONT>转化则有明显误差了</P>
<P ><p><FONT face="Times New Roman"> </FONT></p></P>
<P >怎么办？能求得<FONT face="Times New Roman">b</FONT>、<FONT face="Times New Roman">c</FONT>点坐标</P>