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<p>Hi Rick,</p>
<p>indeed this is what I want. Thanks for the hint!</p>
<p>I was thinking about drawing the map every time again but I
rejected the idea because I have more than 100 flights at one time
step. But I will give it a try now. <span class="moz-smiley-s3"><span>;-)</span></span><br>
</p>
<p>Have a nice weekend!</p>
<p>Karin<br>
</p>
<br>
<div class="moz-cite-prefix">Am 21.05.16 um 17:41 schrieb Rick
Brownrigg:<br>
</div>
<blockquote
cite="mid:CAGKRhbFgX8YS7KHzethwxGyGShqmVwPos7kFJgacF_3W1yBn0A@mail.gmail.com"
type="cite">
<div dir="ltr">
<div>
<div>
<div>Hi Karin,<br>
<br>
</div>
Rather than use gns_add_polyline, which associates the line
with the plot, what about gsn_polyline, which just
graphically overlays the line. I think I was able to
achieve something like what you are after with the attached
script. The essence of the drawing is this:<br>
<br>
deltaLon = (lon2 - lon1) / 5.<br>
deltaLat = (lat2 - lat1) / 5.<br>
do i=0,4<br>
draw(plot1)<br>
gsn_polyline(wks, plot1, (/lon1+deltaLon*i,
lon1+deltaLon*(i+1)/), \<br>
(/lat1+deltaLat*i,
lat1+deltaLat*(i+1)/), \<br>
pres)<br>
frame(wks)<br>
end do<br>
<br>
</div>
Hope that helps...<br>
</div>
Rick<br>
</div>
<div class="gmail_extra"><br>
<div class="gmail_quote">On Fri, May 20, 2016 at 3:50 PM, Karin
Meier-Fleischer <span dir="ltr"><<a moz-do-not-send="true"
href="mailto:meier-fleischer@dkrz.de" target="_blank">meier-fleischer@dkrz.de</a>></span>
wrote:<br>
<blockquote class="gmail_quote" style="margin:0 0 0
.8ex;border-left:1px #ccc solid;padding-left:1ex">Hi,<br>
<br>
is it possible to delete a polyline added to a simple map
plot by<br>
gsn_add_polyline after it was drawn?<br>
<br>
I have flight trace data consisting of many segments per
flight which I<br>
am animating segment by segment. This is not a problem. The
idea now is<br>
to delete the first two segments after drawing 3 segments
and further on<br>
to simulate a moving trace part to the end point (like a
disappearing<br>
trail).<br>
<br>
The following snippet will cause an error:<br>
<br>
do n=0,nsegemnts-1<br>
str = unique_string("trace")<br>
map@$str$ =<br>
gsn_add_polyline(wks,map,(/x(n-1),x(n)/),(/y(n-1),y(n)/),pres)<br>
<br>
if(n .gt. 2) then<br>
trold0 = "trace"+(n-3)<br>
trold1 = "trace"+(n-2)<br>
delete([/map@$trold0$,map@$trold1$/])<br>
end if<br>
<br>
end do<br>
<br>
warning:TransformPostDraw: tfPolyDrawList element 0 is
invalid<br>
warning:TransformPostDraw: tfPolyDrawList element 1 is
invalid<br>
warning:Attempt to reference attribute (trace1) which is
undefined<br>
<br>
<br>
Due to the huge number of segments I would want to 'switch'
the first<br>
segments off, if possible, and not to draw each single plot
from scratch<br>
again for each flight .<br>
<br>
Bye,<br>
Karin<br>
<br>
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</blockquote>
</div>
<br>
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