<div dir="ltr">Hi Anahita,<div><br></div><div>Just to follow up on this, my colleague Mary has added some examples of how to draw reference lines, which are much easier and cleaner than the code I suggested. Check out examples 36/36_vref at:</div><div><br></div><div><a href="http://www.ncl.ucar.edu/Applications/xy.shtml#ex36">http://www.ncl.ucar.edu/Applications/xy.shtml#ex36</a><br></div><div><br></div><div>Thanks Mary!</div><div><br></div><div>Rick</div><div><br></div><div class="gmail_extra"><br><div class="gmail_quote">On Thu, Mar 30, 2017 at 7:44 AM, Rick Brownrigg <span dir="ltr"><<a href="mailto:brownrig@ucar.edu" target="_blank">brownrig@ucar.edu</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left-width:1px;border-left-style:solid;border-left-color:rgb(204,204,204);padding-left:1ex"><div dir="ltr"><div><div><div><div><div><div><div><div><div><br>HI,<br><br></div>One way would be to use gsn_add_polyline():<br><br> <a href="http://ncl.ucar.edu/Document/Graphics/Interfaces/gsn_add_polyline.shtml" target="_blank">http://ncl.ucar.edu/Document/<wbr>Graphics/Interfaces/gsn_add_<wbr>polyline.shtml</a><br><br></div>In short after each plot, you'd set up the line resources the way you want, and call this function 3 times for each plot for each of the three altitudes. Note that you need to assign the results returned by the function to a unique variable, as the lines (nor the plots) aren't actually drawn until the call to gsn_panel. So, for the first plot, something like:<br><br></div><div> ; these 3 lines done once...<br></div> lines = new((/12/), graphic) ; variable to hold the 12 lines<br></div> lnres = True<br></div><div> lnnum = 0<br></div><div><br></div> plot(0) = gsn_csm_xy(......)<br></div> lnres@gsLineColor = "red"<br></div> lnres@gsLineDashPattern = ...<br></div> lines(lnnum) = gsn_add_polyline(wks, plot(0), (/res@trXMinF, res@trXMaxF/), (/1., 1./), lnres)<br></div> lnnum = lnnum + 1<br><br> lnres@gsLineColor = "blue<br> lnres@gsLineDashPattern = ...<br> lines(lnnum) = gsn_add_polyline(wks, plot(0), (/res@trXMinF, res@trXMaxF/), (/2., 2./), lnres)<br> lnnum = lnnum + 1<br><br> lnres@gsLineColor = "green"<br> lnres@gsLineDashPattern = ...<br> lines(lnnum) = gsn_add_polyline(wks, plot(0), (/res@trXMinF, res@trXMaxF/), (/3., 3./), lnres)<br> lnnum = lnnum + 1<br><div> <br></div><div>And so on. This is a bit tedious, and there are other ways to structure this, eg, you could draw all the plots, then add the lines looping over the plots, etc. I'd probably turn the line drawing part into a function, passing in the colors, patterns, wks, and plot number, returning the line result. <br><br></div><div>Hope that helps...<br></div><div>Rick<br></div><div class="gmail_extra"><br><div class="gmail_quote"><div><div class="gmail-h5">On Wed, Mar 29, 2017 at 10:17 PM, Anahita Amiri Farahani <span dir="ltr"><<a href="mailto:aamir003@ucr.edu" target="_blank">aamir003@ucr.edu</a>></span> wrote:<br></div></div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left-width:1px;border-left-style:solid;border-left-color:rgb(204,204,204);padding-left:1ex"><div><div class="gmail-h5"><div dir="ltr">Hello all,<div><br></div><div>I want to add three horizontal constant lines (solid and dashed) at different altitudes (1,2, and 3 km) with different colors to my plot but I don't know how to do it. I have attached the figure and the code.</div><div><br></div><div><br></div><div><br></div><div><div><br></div><div> wks = gsn_open_wks("eps","vertical_w<wbr>hole")</div><div>; gsn_define_colormap(wks,"gui_d<wbr>efault")</div><div> plot = new(4,graphic) </div><div>;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;<wbr>;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;<wbr>;;;;;;;;;;;;</div><div> res = True ; plot mods desired</div><div>res@gsnFrame = False ; don't draw yet</div><div> res@gsnDraw = False ; don't advance frame yet</div><div> </div><div>res@tiXAxisString = "Dust extinction coefficient" ; xaxis string</div><div> res@tiYAxisString = "Altitude (km)" ; yaxis string</div><div>;res@trYReverse = True ; reverse Y-axis</div><div><br></div><div> res@trYMinF = -1<span class="gmail-m_-7810792211446382432m_3664759842630205777gmail-Apple-tab-span" style="white-space:pre-wrap"> </span>; set minimum Y-axis value</div><div> res@trYMaxF = 10<span class="gmail-m_-7810792211446382432m_3664759842630205777gmail-Apple-tab-span" style="white-space:pre-wrap"> </span>; set maximum Y-axis value</div><div> res@trXMinF = 0 ; set minimum X-axis value</div><div> res@trXMaxF = 0.06 ; set maximum X-axis value</div><div><br></div><div> </div><div>;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;<wbr>;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;<wbr>;;;;;;;;;;;;</div><div><br></div><div>res@gsnLeftString = "Winter" ; change left string</div><div>plot(0) = gsn_csm_xy(wks,extinct_winter_<wbr>avg2,alt,res)</div><div>res@gsnLeftString = "Spring" ; change left string</div><div>plot(1) = gsn_csm_xy(wks,extinct_spring_<wbr>avg2,alt,res)</div><div>res@gsnLeftString = "Summer" ; change left string</div><div>plot(2) = gsn_csm_xy(wks,extinct_summer_<wbr>avg2,alt,res)</div><div>res@gsnLeftString = "Fall" ; change left string</div><div>plot(3) = gsn_csm_xy(wks,extinct_fall_av<wbr>g2,alt,res)</div><div>;*****************************<wbr>*******************</div><div>; create panel</div><div>;*****************************<wbr>*******************</div><div>resP = True ; modify the panel plot</div><div><br></div><div> resP@gsnPanelFigureStrings = (/"a)","b)","c)","d)"/) ; add strings to panel</div><div> gsn_panel(wks,plot,(/2,2/),re<wbr>sP) </div><div><br></div><div><br></div><div>delete(plot)</div><div>delete(res)</div><div>delete(resP)</div><div>delete(wks)</div><div><br></div></div><div><br></div><div><br></div><div><br></div><div>Thanks,</div><div>Ana</div></div>
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