<P>Dear Kishore£¬</P>
<P>I followed with your suggestion and run the next check gs file:</P>
<P>'sdfopen d:/grads/mada/data.cdf'<BR>'open d:/grads/mada/maskout_china.ctl'<BR>'set lon 61.25 143.75'<BR>'set lat -8.75 56.25'<BR>'set lev 0 0'<BR>'set e 1 1'<BR>'set t 114'<BR>'d maskout(pdsi,1)'<BR>; <BR>It shows all the area instead of china. So I changed my gs file following your suggestion, but it showed some errors as below:</P>
<P>data request error: invalid grid coordinates</P>
<P>world coordinates convert to non-integer grid coordinates</P>
<P>variable=mask.2 dimension=3</P>
<P>operation errer: error from maskout function and aave function and tloop function</P>
<P>and so on...</P>
<P>then I checked mask.2:</P>
<P>'sdfopen d:/grads/mada/data.cdf'<BR>'open d:/grads/mada/maskout_china.ctl'<BR>'set lon 61.25 143.75'<BR>'set lat -8.75 56.25'<BR>'set lev 0 0'<BR>'set e 1 1'<BR>'set t 114'<BR>'d maskout(pdsi,mask.2)'<BR>;</P>
<P>well, it also showed some errors:</P>
<P>data request error: invalid grid coordinates</P>
<P>world coordinates convert to non-integer grid coordinates</P>
<P>variable=mask.2 dimension=3</P>
<P>operation errer: error from maskout function </P>
<P>error ocurred at column 1</P>
<P>display error: invalid expression</P>
<P>expression= maskout(pdsi,mask.2)</P>
<P> </P>
<P>What's wrong with it? Does the ctl file I changed have some errors or other problems?</P>
<P>Thanks a lot! Best regards!</P>
<P>Zhihong<BR><SPAN><BR></SPAN></P>
<P> Zhihong Zhuo,Postgraduate Student</P>
<P><FONT face="Times New Roman"> College of Environmental and Resource Sciences, Zhejiang University</FONT></P>
<P><FONT face="Times New Roman">Address: 866 Yuhangtan Road, Hangzhou, China</FONT></P>
<P><FONT face="Times New Roman">Email: <A href="mailto:fairyes@zju.edu.cn" target="_blank">fairyes@zju.edu.cn</A></FONT></P>
<P><FONT face="Times New Roman"></FONT> </P>