<div dir="ltr">Hi Dennis,<div>Yes, you are right Height is just added as the label for right-Y axis, not like gsn_csm_xy2.ncl. I searched "<span style="font-size:18px">gsn_csm_pres_hgt_vec</span><span style="font-size:18px">tor</span>" the code (<span style="font-family:Courier;font-size:14px">gsn_csm.ncl</span>). However, I did not find how it calculates the height using pressure value. Do you know who wrote this code (<span style="font-family:Courier;font-size:14px">gsn_csm.ncl</span>) or do you know who is more familiar with this code? Thank you,</div><div><br></div><div>Zhifeng</div></div><div class="gmail_extra"><br><div class="gmail_quote">On Thu, Aug 20, 2015 at 10:31 AM, Dennis Shea <span dir="ltr"><<a href="mailto:shea@ucar.edu" target="_blank">shea@ucar.edu</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><span class="">" I am not sure how to add a polyline using the right y-axis"<br>
<br>
</span>I did not write this so I am guessing:<br>
<br>
I think the right-y-axis ("Height") is not a y-coordinate. Rather,<br>
'under-the-hood,' a function (say) Height = f(pressure) was used to<br>
estimate the heights for labeling purposes.<br>
<br>
if the x-axis is (say, lat or lon), and you have:<br>
polyline_values = f(x,height)<br>
then you may have to recast the 2nd line in terms of pressure and add<br>
like the 1st polyline<br>
<div><div class="h5"><br>
<br>
<br>
<br>
<br>
On Wed, Aug 19, 2015 at 2:16 PM, Zhifeng Yang <<a href="mailto:yangzf01@gmail.com">yangzf01@gmail.com</a>> wrote:<br>
> Hi<br>
><br>
> Sorry for posting this problem again. Since I haven't received reply from my<br>
> previous post, I promote it by myself.<br>
><br>
> I want to add a polyline on a image generated by gsn_csm_pres_hgt_vector,<br>
> and the y value of the polyline is height, which is the right y-axis. I can<br>
> add a polyline using the left y-axis, but I need to reverse pressure to plot<br>
> a polyline. I don't know how to plot a polyline with reversed y-axis. Most<br>
> important, I am not sure how to add a polyline using the right y-axis. Do<br>
> you know how to fix it?<br>
> Thank you.<br>
><br>
> Best,<br>
> Zhifeng<br>
><br>
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</blockquote></div><br></div>