<div dir="ltr"><div class="gmail_default" style="font-size:small">Xiaoming,</div><div class="gmail_default" style="font-size:small"><br></div><div class="gmail_default" style="font-size:small">You have an out-dated function call (WRF_map_c) that might possibly be the source of the problem. This is a deprecated function and you should use wrf_map_resources to set your WRF map projection instead:</div><div class="gmail_default" style="font-size:small"><br></div><div class="gmail_default"><a href="http://www.ncl.ucar.edu/Document/Functions/WRF_arw/wrf_map_resources.shtml">http://www.ncl.ucar.edu/Document/Functions/WRF_arw/wrf_map_resources.shtml<br></a></div><div class="gmail_default"><br></div><div class="gmail_default">I can't tell from your code why the two results are different, because it's not clear to me if the only thing you are changing is whether or not tfDoNDCOverlay is set.</div><div class="gmail_default"><br></div><div class="gmail_default">If I'm understanding your email correctly, it sounds like the plot that is created when <span style="color:rgb(34,34,34);font-family:arial,sans-serif;font-size:small;font-style:normal;font-variant-ligatures:normal;font-variant-caps:normal;font-weight:400;letter-spacing:normal;text-align:start;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px;background-color:rgb(255,255,255);text-decoration-style:initial;text-decoration-color:initial;float:none;display:inline">tfDoNDCOverlay is set to True is the one that's correct. However, I'm surprised it's working for you because:</span></div><div class="gmail_default"><br></div><div class="gmail_default">[1] If you set tfDoNDCOverlay to True, you should NOT attach any lat2d/lon2d attributes to your data variables.</div><div class="gmail_default"><br></div><div class="gmail_default">[2] Also, if <span style="color:rgb(34,34,34);font-family:arial,sans-serif;font-size:small;font-style:normal;font-variant-ligatures:normal;font-variant-caps:normal;font-weight:400;letter-spacing:normal;text-align:start;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px;background-color:rgb(255,255,255);text-decoration-style:initial;text-decoration-color:initial;float:none;display:inline">tfDoNDCOverlay is True, you must be using the EXACT map projection that was defined on the file. But, you are using WRF_map_c which hasn't been updated in years, so this function could likely be giving you wrong results. Also, you are setting:</span></div><br> n_cutoff = 150<br> res@mpLeftCornerLonF = lon2d(0,n_cutoff)<br> res@mpLeftCornerLatF = lat2d(0,n_cutoff)<div class="gmail_default"><span style="color:rgb(34,34,34);font-family:arial,sans-serif;font-size:small;font-style:normal;font-variant-ligatures:normal;font-variant-caps:normal;font-weight:400;letter-spacing:normal;text-align:start;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px;background-color:rgb(255,255,255);text-decoration-style:initial;text-decoration-color:initial;float:none;display:inline"><br></span></div><div class="gmail_default"><span style="color:rgb(34,34,34);font-family:arial,sans-serif;font-size:small;font-style:normal;font-variant-ligatures:normal;font-variant-caps:normal;font-weight:400;letter-spacing:normal;text-align:start;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px;background-color:rgb(255,255,255);text-decoration-style:initial;text-decoration-color:initial;float:none;display:inline">which looks to me like you are zooming in on the map, but you haven't also zoomed in on the data in the same way, so again, I don't know how your plots can be correct.</span></div><div class="gmail_default"><span style="color:rgb(34,34,34);font-family:arial,sans-serif;font-size:small;font-style:normal;font-variant-ligatures:normal;font-variant-caps:normal;font-weight:400;letter-spacing:normal;text-align:start;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px;background-color:rgb(255,255,255);text-decoration-style:initial;text-decoration-color:initial;float:none;display:inline"><br></span></div><div class="gmail_default">[3] For the case of tfDoNDCOverlay not being set, you may need to set res@gsnAddCyclic = False to prevent a longitude cyclic point from being added.</div><div class="gmail_default"><br></div><div class="gmail_default">Please visit this WRF examples page, which has examples of plotting WRF data with both tfDoNDCOverlay set and without it set:</div><div class="gmail_default"><br></div><div class="gmail_default"><a href="http://www.ncl.ucar.edu/Applications/wrfgsn.shtml">http://www.ncl.ucar.edu/Applications/wrfgsn.shtml</a><br></div><div class="gmail_default"><br></div><div class="gmail_default">I've attached two modified versions of your script. Since I don't have the data, I am unable to test these scripts. But, hopefully they help show the difference between these two scenarios.</div><div class="gmail_default"><br></div><div class="gmail_default">If you continue to have problems with this, please post back to ncl-talk, but include a clean, updated script if possible.</div><div class="gmail_default"><br></div><div class="gmail_default">Good luck,</div><div class="gmail_default"><br></div><div class="gmail_default">--Mary</div><div class="gmail_default"><br></div><div class="gmail_default"><span style="color:rgb(34,34,34);font-family:arial,sans-serif;font-size:small;font-style:normal;font-variant-ligatures:normal;font-variant-caps:normal;font-weight:400;letter-spacing:normal;text-align:start;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px;background-color:rgb(255,255,255);text-decoration-style:initial;text-decoration-color:initial;float:none;display:inline"><br></span></div><div class="gmail_default"><span style="color:rgb(34,34,34);font-family:arial,sans-serif;font-size:small;font-style:normal;font-variant-ligatures:normal;font-variant-caps:normal;font-weight:400;letter-spacing:normal;text-align:start;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px;background-color:rgb(255,255,255);text-decoration-style:initial;text-decoration-color:initial;float:none;display:inline"><br></span></div><div class="gmail_default"><span style="color:rgb(34,34,34);font-family:arial,sans-serif;font-size:small;font-style:normal;font-variant-ligatures:normal;font-variant-caps:normal;font-weight:400;letter-spacing:normal;text-align:start;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px;background-color:rgb(255,255,255);text-decoration-style:initial;text-decoration-color:initial;float:none;display:inline"><br></span></div><div class="gmail_default"><br></div><div class="gmail_default"><br></div></div><div class="gmail_extra"><br><div class="gmail_quote">On Tue, Apr 17, 2018 at 11:04 PM, xiaoming Hu <span dir="ltr"><<a href="mailto:yuanfangcan@hotmail.com" target="_blank">yuanfangcan@hotmail.com</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
<div dir="ltr">
<div id="m_-1516211398501258156divtagdefaultwrapper" style="font-size:12pt;color:#000000;font-family:Calibri,Helvetica,sans-serif" dir="ltr">
<p style="margin-top:0;margin-bottom:0">Hello </p>
<p style="margin-top:0;margin-bottom:0"><br>
</p>
<p style="margin-top:0;margin-bottom:0"> If I use <span>res@tfDoNDCOverlay I got the figure of </span></p>
<p style="margin-top:0;margin-bottom:0"><span><img size="662339" id="m_-1516211398501258156img109800" style="max-width:99.9%" src="cid:c0f4f858-bf59-4f1a-9241-88c9b68f655f"><br>
</span></p>
<p style="margin-top:0;margin-bottom:0"><span>But If I use @lat2d @lon2d without <span style="font-family:Calibri,Helvetica,sans-serif,EmojiFont,"Apple Color Emoji","Segoe UI Emoji",NotoColorEmoji,"Segoe UI Symbol","Android Emoji",EmojiSymbols;font-size:16px">res@tfDoNDCOverlay
I got</span></span></p>
<p style="margin-top:0;margin-bottom:0"><span><span style="font-family:Calibri,Helvetica,sans-serif,EmojiFont,"Apple Color Emoji","Segoe UI Emoji",NotoColorEmoji,"Segoe UI Symbol","Android Emoji",EmojiSymbols;font-size:16px"><img size="660617" id="m_-1516211398501258156img558532" style="max-width:99.9%" src="cid:5108a2f1-0cbf-4ea5-9260-f9aabdf866a4"><br>
</span></span></p>
<p style="margin-top:0;margin-bottom:0"><span>The wind vectors near the right edge in the left panel do not follow the pressure lines now. </span></p>
<p style="margin-top:0;margin-bottom:0"><span><br>
</span></p>
<p style="margin-top:0;margin-bottom:0"><span>Any comments on overlaying wind vectors using <span style="font-family:Calibri,Helvetica,sans-serif,EmojiFont,"Apple Color Emoji","Segoe UI Emoji",NotoColorEmoji,"Segoe UI Symbol","Android Emoji",EmojiSymbols;font-size:16px">res@tfDoNDCOverlay
or using <span style="font-family:Calibri,Helvetica,sans-serif,EmojiFont,"Apple Color Emoji","Segoe UI Emoji",NotoColorEmoji,"Segoe UI Symbol","Android Emoji",EmojiSymbols;font-size:16px">@lat2d @lon2d without </span><span style="font-family:Calibri,Helvetica,sans-serif,EmojiFont,"Apple Color Emoji","Segoe UI Emoji",NotoColorEmoji,"Segoe UI Symbol","Android Emoji",EmojiSymbols;font-size:16px">res@tfDoNDCOverlay
? </span></span></span></p>
<p style="margin-top:0;margin-bottom:0"><span><span style="font-family:Calibri,Helvetica,sans-serif,EmojiFont,"Apple Color Emoji","Segoe UI Emoji",NotoColorEmoji,"Segoe UI Symbol","Android Emoji",EmojiSymbols;font-size:16px"><span style="font-family:Calibri,Helvetica,sans-serif,EmojiFont,"Apple Color Emoji","Segoe UI Emoji",NotoColorEmoji,"Segoe UI Symbol","Android Emoji",EmojiSymbols;font-size:16px">I
attached my ncl script </span></span></span></p>
<p style="margin-top:0;margin-bottom:0"><span><span style="font-family:Calibri,Helvetica,sans-serif,EmojiFont,"Apple Color Emoji","Segoe UI Emoji",NotoColorEmoji,"Segoe UI Symbol","Android Emoji",EmojiSymbols;font-size:16px"><span style="font-family:Calibri,Helvetica,sans-serif,EmojiFont,"Apple Color Emoji","Segoe UI Emoji",NotoColorEmoji,"Segoe UI Symbol","Android Emoji",EmojiSymbols;font-size:16px">Thanks</span></span></span></p><span class="HOEnZb"><font color="#888888">
<p style="margin-top:0;margin-bottom:0"><span><span style="font-family:Calibri,Helvetica,sans-serif,EmojiFont,"Apple Color Emoji","Segoe UI Emoji",NotoColorEmoji,"Segoe UI Symbol","Android Emoji",EmojiSymbols;font-size:16px"><span style="font-family:Calibri,Helvetica,sans-serif,EmojiFont,"Apple Color Emoji","Segoe UI Emoji",NotoColorEmoji,"Segoe UI Symbol","Android Emoji",EmojiSymbols;font-size:16px">Xiaoming </span></span></span></p>
<p style="margin-top:0;margin-bottom:0"><span><br>
</span></p>
</font></span></div>
</div>
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