First, define a variable that only includes the area contained within the 5400 contour. The following will do the trick:<br><br>"define vortex = const(maskout(height,5400),1)"<br><br>Then compute the centroid.<br>
<br>"define xsum = sum(lon,[some horizontal limit that fits the entire contour within it])"<br>"define ysum = sum(lat,[some meridional limit that fits the entire contour within it])"<br>longitude of centroid: "d xsum / asum(vortex,[x limits],[y limits])"<br>
latitude of centroid: "d ysum / asum(vortex,[x limits],[y limits])"<br><br><br>Jeff Duda<br><br><div class="gmail_quote">On Sun, Apr 8, 2012 at 11:14 PM, Abdolreza Kashki <span dir="ltr"><<a href="mailto:r.kashki@yahoo.com">r.kashki@yahoo.com</a>></span> wrote:<br>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div><div style="font-size:12pt;font-family:times new roman,new york,times,serif"><div><span>Dear all,</span></div><div>
<span>How can I calculate the Centriod(lat,lon) of a specific contour e.g. 5400 gpm contour in 500 hpa level in degree in Grads software?</span></div><div><span>Best Regards</span></div><div><span>kashki<var></var></span></div>
<div></div><div> </div><div>Abdolreza Kashki <br>Ph.D. Student of Climatology<br>Department of Physical Geography<br>Faculty of Planing & Geography Science <br>University of Isfahan <br>Isfahan, Iran<br>Postcode:81746-73441<br>
Tel:+98(311)7933119<br>Fax:+98(311)7932257<br>Cell:+989151731453</div></div></div><br>_______________________________________________<br>
gradsusr mailing list<br>
<a href="mailto:gradsusr@gradsusr.org">gradsusr@gradsusr.org</a><br>
<a href="http://gradsusr.org/mailman/listinfo/gradsusr" target="_blank">http://gradsusr.org/mailman/listinfo/gradsusr</a><br>
<br></blockquote></div><br><br clear="all"><br>-- <br>Jeff Duda<br>Graduate research assistant<br>University of Oklahoma School of Meteorology<br>Center for Analysis and Prediction of Storms<br><br>