<div dir="ltr">Hi Chang,<div>As Mary noted this is a user-donated function and thus is not officially supported by the NCL project. However, I was able to get an arrow drawn on the first example of the latitude x height applications page by using the donated arrow function here:</div><div><a href="http://www.ncl.ucar.edu/Applications/height_lat.shtml#ex1">http://www.ncl.ucar.edu/Applications/height_lat.shtml#ex1</a></div><div><br></div><div>I have attached the modified version of h_lat_1.ncl along with the resulting graphic. Note that you can pass gs resources into the arrow function to modify the color, thickness, etc as is shown on the polyline applications page here:</div><div><a href="http://www.ncl.ucar.edu/Applications/polyg.shtml">http://www.ncl.ucar.edu/Applications/polyg.shtml</a><br></div><div><br></div><div>Hope that helps. If you have any further questions please respond to the ncl-talk email list.</div><div>Adam</div><div><br></div><div><br></div><div> </div></div><div class="gmail_extra"><br><div class="gmail_quote">On Mon, Jun 19, 2017 at 11:33 AM, Mary Haley <span dir="ltr"><<a href="mailto:haley@ucar.edu" target="_blank">haley@ucar.edu</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 class="gmail_default" style="font-size:small">Chang,</div><div class="gmail_default" style="font-size:small"><br></div><div class="gmail_default" style="font-size:small">This is a user-donated function that I am unfamiliar with.</div><div class="gmail_default" style="font-size:small"><br></div><div class="gmail_default" style="font-size:small">The code seems straight-forward enough. If the head is simply at the wrong end of the vector, then you should be able to change arrow.ncl to swap which end the head is considered to be.</div><div class="gmail_default" style="font-size:small"><br></div><div class="gmail_default" style="font-size:small">If you are trying to create a pressure/latitutde plot with vectors, then you may want to look into gsn_csm_pres_hgt_vector. This requires that you have a 2D array of U and V values which you will need to seed with your own values:</div><div class="gmail_default" style="font-size:small"><br></div><div class="gmail_default"><a href="http://www.ncl.ucar.edu/Document/Graphics/Interfaces/gsn_csm_pres_hgt_vector.shtml" target="_blank">http://www.ncl.ucar.edu/<wbr>Document/Graphics/Interfaces/<wbr>gsn_csm_pres_hgt_vector.shtml</a><br><br></div><div class="gmail_default">--Mary</div><div class="gmail_default"><br></div></div><div class="gmail_extra"><br><div class="gmail_quote">On Mon, Jun 19, 2017 at 10:19 AM, Xi Chang <span dir="ltr"><<a href="mailto:xi.chang01@gmail.com" target="_blank">xi.chang01@gmail.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"><span style="font-size:12.8px">Hi Mary and NCL,</span><div style="font-size:12.8px"><br></div><div style="font-size:12.8px">The script for the arrow-<span class="m_5599083120790727081m_-5333555315812482661gmail-il">head</span> can only work in the X and Y are in cartesian coordinate. It did NOT work when <b>X is the latitude and Y is the height</b> (hPa), the head of the vector is placed wrongly when I used "polylines" function. Can you help me with this issue?</div><div style="font-size:12.8px"><br></div><div style="font-size:12.8px">Best,</div><div style="font-size:12.8px"><span style="font-size:12.8px"><br></span></div><div style="font-size:12.8px"><span style="font-size:12.8px">Chang</span><br></div><div style="font-size:12.8px"><br></div><div style="font-size:12.8px"><br></div><div style="font-size:12.8px"><br></div><div style="font-size:12.8px"><br></div><div class="gmail_extra"><br><div class="gmail_quote"><span>On Thu, May 11, 2017 at 3:42 PM, Mary Haley <span dir="ltr"><<a href="mailto:haley@ucar.edu" target="_blank">haley@ucar.edu</a>></span> wrote:<br></span><div><div class="m_5599083120790727081h5"><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div dir="ltr"><div style="font-size:small">Xi,</div><div style="font-size:small"><br></div><div style="font-size:small">I don't think we have any examples of this, but I typed "arrow polyline" in the search box of the NCL home page, and found this post by Arindam Chakraborty:</div><div style="font-size:small"><br></div><div><a href="https://www.ncl.ucar.edu/Support/talk_archives/2010/1344.html" target="_blank">https://www.ncl.ucar.edu/Suppo<wbr>rt/talk_archives/2010/1344.htm<wbr>l</a><br></div><div><br></div><div>I've attached the arrow.ncl script that he included in that post. You should be able to run it as-is.</div><div><br></div><div>--Mary</div><div><br></div></div><div class="gmail_extra"><br><div class="gmail_quote"><div><div class="m_5599083120790727081m_-5333555315812482661h5">On Wed, May 10, 2017 at 5:28 PM, Xi Chang <span dir="ltr"><<a href="mailto:xi.chang01@gmail.com" target="_blank">xi.chang01@gmail.com</a>></span> wrote:<br></div></div><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div><div class="m_5599083120790727081m_-5333555315812482661h5"><div dir="ltr">Dear NCL,<div><br></div><div>Is there any a function to <span style="color:rgb(0,0,0)">add an arrow head to show the direction of a line (using polylines)?</span></div><div><span style="color:rgb(0,0,0)">Thanks a lot,</span></div><div><span style="color:rgb(0,0,0)"><br></span></div><div><span style="color:rgb(0,0,0)">Best,</span></div><div><span style="color:rgb(0,0,0)">Xi</span></div></div>
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<br></blockquote></div><br><br clear="all"><div><br></div>-- <br><div class="gmail_signature" data-smartmail="gmail_signature"><div dir="ltr"><div><div dir="ltr"><div><div dir="ltr"><div><div dir="ltr"><div><div><div><span><font color="#888888">Adam Phillips <br></font></span></div><span><font color="#888888">Associate Scientist, </font></span><span><font color="#888888">Climate and Global Dynamics Laboratory, NCAR<br></font></span></div></div><div><span><font color="#888888"><a href="http://www.cgd.ucar.edu/staff/asphilli/" target="_blank">www.cgd.ucar.edu/staff/asphilli/</a> </font></span><span><font color="#888888">303-497-1726 </font></span></div><span><font color="#888888"></font></span><div><div><span><font color="#888888"><br></font></span><div><span><font color="#888888"><a href="http://www.cgd.ucar.edu/staff/asphilli" target="_blank"></a></font></span></div></div></div></div></div></div></div></div></div></div></div>
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