Oh ok. I get it now. yeah, I've run into this problem myself. Try using <br><br>u = wind_magnitude * cos(450 - degrees_in_your_data)<br>v = wind_magnitude * sin(450 - degrees_in_your_data)<br><br>Jeff<br><br><div class="gmail_quote">
On Mon, Sep 27, 2010 at 2:26 PM, Gabriel - ud Carvalho <span dir="ltr"><<a href="mailto:gabriel.ud@gmail.com">gabriel.ud@gmail.com</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin: 0pt 0pt 0pt 0.8ex; border-left: 1px solid rgb(204, 204, 204); padding-left: 1ex;">
I think that I was not clear,<div>I canīt do this suggestion because the 'sin' function is oriented to the trigonometric system, which isnīt the system in which my data is oriented. For instance, in my data, a 270 degrees is equivalent to 180 degrees in the trigonometric system. </div>
<div><br></div><div>I hope I am more clear now, even thoug the roughness of my english...:)</div><div><br></div><div>Thanks in advance,</div><div>Gabriel Carvalho</div><div><br><div class="gmail_quote">2010/9/27 Jeffrey Duda <span dir="ltr"><<a href="mailto:jdduda@iastate.edu" target="_blank">jdduda@iastate.edu</a>></span><br>
<blockquote class="gmail_quote" style="margin: 0pt 0pt 0pt 0.8ex; border-left: 1px solid rgb(204, 204, 204); padding-left: 1ex;">Gabriel,<br>As long as your data contains wind direction oriented such that 0 deg in your data refers to a wind blowing to the north (or from the south), then your components can be broken down as:<br>
<br>u = wind_magnitude * sin(direction)<br>
v = wind_magnitude * cos(direction)<br><br>Of course, when actually putting these computations into Grads you will want to change "direction" from degrees to radians.<br><br>Jeff Duda<br><br><div class="gmail_quote">
<div><div></div><div>
On Mon, Sep 27, 2010 at 12:34 PM, Gabriel - ud Carvalho <span dir="ltr"><<a href="mailto:gabriel.ud@gmail.com" target="_blank">gabriel.ud@gmail.com</a>></span> wrote:<br></div></div><blockquote class="gmail_quote" style="margin: 0pt 0pt 0pt 0.8ex; border-left: 1px solid rgb(204, 204, 204); padding-left: 1ex;">
<div><div></div><div>
Hello you all!<div>Here is the deal:</div><div>In my data, the wind direction is in degrees, with a geographic representation (wich means that 0 is at the north and goes clockwise),</div><div>the problem is that to display this data with 'gxout vector', I have to decompose it in 'u' and 'v'. In order to do this, I have to use the trigonometric functions 'sin' and 'cosin'. The problem is here, these functions assume that the input data is with a trigonometric representation (wich means that 0 degrees is eastside and goes anti-clockwise),butthey arenīt, so, it got all messed up.</div>
<div><br></div><div>I donīt know what to do,but I believe that this is a common problem,</div><div>I hope someone will know the answer...</div><div><br></div><div>Sorry about my poor english,</div><div><br></div><div>My best regards,</div>
<div>Gabriel Carvalho</div><font color="#888888"><div><br></div><div> </div><div><br></div>
</font><br></div></div>_______________________________________________<br>
gradsusr mailing list<br>
<a href="mailto:gradsusr@gradsusr.org" target="_blank">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><font color="#888888"><br><br clear="all"><br>-- <br>Jeff Duda<br>Iowa State University<br>Meteorology Graduate Student<br>3134 Agronomy Hall<br><a href="http://www.meteor.iastate.edu/%7Ejdduda" target="_blank">www.meteor.iastate.edu/~jdduda</a><br>
</font><br>_______________________________________________<br>
gradsusr mailing list<br>
<a href="mailto:gradsusr@gradsusr.org" target="_blank">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></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>Iowa State University<br>Meteorology Graduate Student<br>3134 Agronomy Hall<br><a href="http://www.meteor.iastate.edu/~jdduda">www.meteor.iastate.edu/~jdduda</a><br>