Re: how to draw a circle wrapping a few points

Hi,
 sometime ago I've shared a function circle_ll() which can draw
circle/ellipse on a plot with least effort. Please see this thread:
http://www.ncl.ucar.edu/Support/talk_archives/2012/1334.html

This function might help you.

regards,

--
*Dr Arindam Chakraborty*
CAOS, IISc, Bangalore-12*
*
On Tue, Jul 30, 2013 at 3:29 AM, Mary Haley <haley@ucar.edu> wrote:
> There's no automatic function to draw a circle on a plot. The best way to
> do this currently is to use gsn_polyline or gsn_add_polyline. See the
> attached sample script.
>
> You didn't say how you wanted to determine where to draw the circle and
> how big. I just used some dummy values in this example.
>
> Note the circle is not perfectly round here. That's because the plot area
> that I'm drawing in has a range of 24 on the Y axis, and 21 on the X axis.
>
> If you uncomment these lines, the circle will be perfectly round:
>
> ;  res@trXMinF          = xmin
> ;  res@trXMaxF          = xmax
> ;  res@trYMinF          = ymin
> ;  res@trYMaxF          = ymax
>
>
>
> --Mary
>
>
>
> On Jul 27, 2013, at 4:47 PM, 雷霆 <leiting2002@hotmail.com> wrote:
>
> Dear NCLers,
> For several curves plotted by gsn_xy, I want to draw,say, an empty circle
> to
> wrap  a few points in the former. I checked up with the ncl-talk archive,
> seems, to draw a marker of cycles can do this.
> However, that needs much tuning of the radius of the marker (circles,
> here) to do it.
> Are there any simpler methods in NCL to do this?
> Your help is appreciated.
> Best,
> Ting Lei
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Received on Tue Jul 30 05:39:47 2013