<div dir="ltr">An alternative:<br><br>nggog can be used. Sample code segments follow. For small radii Npts=100 is fine but for large radii and nice circles, Npts=360 might be better.<br><br>;=========================================================================<br>; On a sphere with radius 6371 km, one degree is approximately 110.57 km.<br>;---<br>; Of course, the earth is an oblate spheroid:<br>;      <a href="http://www.longitudestore.com/how-big-is-one-gps-degree.html">http://www.longitudestore.com/how-big-is-one-gps-degree.html</a><br>;=========================================================================<br>; <a href="https://www.ncl.ucar.edu/Document/Functions/Built-in/nggcog.shtml">https://www.ncl.ucar.edu/Document/Functions/Built-in/nggcog.shtml</a><br>;=========================================================================<br><br>;---One station<br><br>   slat     = 0.0                  ; station lat<br>   slon     = 0.0                  ;         lon<br>   srad_km  = (/ 50, 100, 150, 5*110.57/)*1.0  ; station radii (km)<br>   km2deg   = 1/110.57             ; conversion factor: deg ==> km<br>                                   ; one degree is approximately 110.57 km.<br>   srad_dg  = srad_km*km2deg       ; km ==> deg; nggcog requires degrees<br><br>   Nrad = dimsizes(srad_dg)        ; # of radii<br>   Npts = 100                      ; # of points at each radii (arbitrary) <br><br>   Rlat = new((/Nrad, Npts/), "float")    ; lat at each radius<br>   Rlon = new((/Nrad, Npts/), "float")<br><br>   do nr=0,Nrad-1<br>      print("nr="+nr+" srad_km="+srad_km(nr)+";   srad_dg="+srad_dg(nr))<br>      print("")<br><br>      nggcog(slat, slon, srad_dg(nr), Rlat(nr,:), Rlon(nr,:))<br><br>      print(Rlat(nr,:)+"   "+ Rlon(nr,:))<br>      print("========")<br>   end do<br><br>+++++++++++++++++++++++++++++++++++++++++++++++++++++<br>;---Multiple stations<br><br>   slat     = (/ 0.0, 50.0     /)  ; station lat<br>   slon     = (/ 0.0, 30.0     /)  ;         lon<br>   srad_km  = (/ 50, 100, 150, 5*110.57/)*1.0  ; station radii (km)<br>   km2deg   = 1/110.57                ; conversion factor: deg ==> km<br>                                                    ; one degree is approximately 110.57 km.<br>   srad_dg  = srad_km*km2deg   ; km ==> deg; nggcog requires degrees<br>   Nrad     = dimsizes(srad_dg)    ; # of radii<br><br>   Nsta     = dimsizes(slat)            ; # stations<br>   Nrad     = dimsizes(srad)          ; # of radii<br>   Npts     = 100                            ; # of points at each radii (arbitrary; eg 360) <br><br>   Rlat = new((/Nsta, Nrad, Npts/), "float")    ; lat at each radius<br>   Rlon = new((/Nsta, Nrad, Npts/), "float")<br><br>   do ns=0,Nsta-1<br>     do nr=0,Nrad-1<br>        nggcog(slat(ns), slon(ns), srad(nr), Rlat(ns,nr,:), Rlon((ns,nr,:))<br>     end do<br>   end do<br><br></div><div class="gmail_extra"><br><div class="gmail_quote">On Thu, Feb 8, 2018 at 2:38 AM, Karin Meier-Fleischer <span dir="ltr"><<a 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">
  
    
  
  <div text="#000000" bgcolor="#FFFFFF">
    Hi Soumik,<br>
    <br>
    you can use polymarkers to plot the circles around lat/lon
    locations. Have a look at example newcolor_4.ncl at <a href="http://ncl.ucar.edu/Applications/Scripts/newcolor_4.ncl" target="_blank">http://ncl.ucar.edu/<wbr>Applications/Scripts/newcolor_<wbr>4.ncl</a><br>
    <br>
    I've attached an example script using random data for marker size
    and lat/lon locations overlayed on filled contour map.<br>
    <br>
    Hope this helps.<br>
    <br>
    -Karin<br>
    <br>
    <div class="m_-3527953815923975900moz-cite-prefix">Am 08.02.18 um 00:55 schrieb Soumik
      Basu:<br>
    </div>
    <blockquote type="cite"><div><div class="h5">
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        <div>
          <div>
            <div>
              <div>Hello NCL-users,<br>
                <br>
              </div>
              I am trying to draw circles around a station with
              different radius. For example 50 Km, 100 Km, 150 Km etc. <br>
              <br>
              So, I am wondering if there is any way to do it in NCL. <br>
              <br>
              I looked at the "nggcog" function but from the description
              what I understand is that it can draw circles along a
              great circle only not according to a given distance. <br>
              <br>
            </div>
            Thank you for any help. <br>
            <br>
          </div>
          Thanks,<br>
        </div>
        Soumik<br clear="all">
        <div>
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              <div>
                <div><br>
                  -- <br>
                  <div class="m_-3527953815923975900gmail_signature">
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                      <div>
                        <div dir="ltr">
                          <div>-- </div>
                          “We’ve all got both light and dark inside us.
                          What matters is the part we choose to act on.
                          That’s who we really are.” – J.K. Rowling
                          <div><br>
                          </div>
                          <div>******************************<wbr>******************************<wbr>******************************<wbr>********</div>
                          <div>Dr. Soumik Basu</div>
                          <div>Post Doctoral Research Faculty</div>
                          <div><span style="font-size:12.8px">International
                              Arctic Research Center, UAF, Fairbanks,
                              AK, USA</span></div>
                          <div><span style="font-size:12.8px">PhD in
                              Atmospheric Sciences</span><br>
                          </div>
                          <div>M.Sc. in Atmospheric Sciences</div>
                          <div>Email: <a href="mailto:suvro05@gmail.com" target="_blank">suvro05@gmail.com</a></div>
                          <div>website: <a href="http://soumikbasu.weebly.com/" target="_blank">http://soumikbasu.weebly.com/</a></div>
                          <div><br>
                          </div>
                          <div>******************************<wbr>******************************<wbr>******************************<wbr>*********</div>
                        </div>
                      </div>
                    </div>
                  </div>
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      <br>
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      <br>
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    </span></blockquote>
    <br>
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