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<p class="MsoNormal">Try adding or subtracting 360 to the longitudes. Sometimes I see 0 to 360, sometimes -180 to 180. (-360 to 0 is new to me.)<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
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<p class="MsoNormal"><span style="color:black">_______________________________________________________</span><span style="font-size:12.0pt;color:black"><o:p></o:p></span></p>
<p class="MsoNormal"><i><span style="color:black">Clay Blankenship, USRA Atmospheric Scientist</span></i><i><span style="font-size:12.0pt;color:black"><o:p></o:p></span></i></p>
<p class="MsoNormal"><i><span style="color:black">NASA Short-term Prediction Research and Transition Center (SPoRT)<o:p></o:p></span></i></p>
<p class="MsoNormal"><i><span style="color:black">Marshall Space Flight Center, Huntsville, Alabama</span></i><i><span style="font-size:12.0pt;color:black"><o:p></o:p></span></i></p>
<p class="MsoNormal"><i><span style="font-size:12.0pt;color:black"> <o:p></o:p></span></i></p>
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<p class="MsoNormal"><b><span style="font-size:12.0pt;color:black">From: </span></b><span style="font-size:12.0pt;color:black">gradsusr <gradsusr-bounces@gradsusr.org> on behalf of Raphael Ranieri <raphaelcr93@hotmail.com><br>
<b>Reply-To: </b>GrADS Users Forum <gradsusr@gradsusr.org><br>
<b>Date: </b>Thursday, August 13, 2020 at 7:19 AM<br>
<b>To: </b>"gradsusr@gradsusr.org" <gradsusr@gradsusr.org><br>
<b>Subject: </b>[EXTERNAL] [gradsusr] Negative Longitude of -360 in xdef of ctl file<o:p></o:p></span></p>
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<p class="MsoNormal">Hello All, <o:p></o:p></p>
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<p class="MsoNormal">I'm trying to use some files of a Brazillian institute of meteorology and I'm facing a problem with the longitude values.<o:p></o:p></p>
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<p class="MsoNormal"><o:p> </o:p></p>
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<p class="MsoNormal">They used grads to create a ctl file that can be accessed in this FTP from the institution:<o:p></o:p></p>
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<p class="MsoNormal">http://ftp.cptec.inpe.br/modelos/tempo/BAM/TQ0666L064/recortes/regioes/2020/07/29/00/BAM_CO_2020072900.ctl<o:p></o:p></p>
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<p class="MsoNormal"><o:p> </o:p></p>
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<p class="MsoNormal"><img width="1684" height="616" style="width:17.5416in;height:6.4166in" id="_x0000_i1025" src="cid:image001.png@01D67155.DD331680"><o:p></o:p></p>
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<p class="MsoNormal"><o:p> </o:p></p>
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<p class="MsoNormal">Here we can see that they are using a linear mapping for xdef with a 0.18 step starting from a longitude of -360 degrees according to GrADs docs:<o:p></o:p></p>
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<p class="MsoNormal">http://cola.gmu.edu/grads/gadoc/descriptorfile.html#XDEF<o:p></o:p></p>
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<p class="MsoNormal"><o:p> </o:p></p>
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<p class="MsoNormal">Since in our case we need the actual longitude and latitude of a point, when we try to read this file we receive longitudes of 360 for example, which do not correspond to any existing longitude.<o:p></o:p></p>
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<p class="MsoNormal"><o:p> </o:p></p>
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<p class="MsoNormal">We are not using Grads to open the file, we are using pygrib ... to use it in a python program.<o:p></o:p></p>
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<p class="MsoNormal"><o:p> </o:p></p>
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<p class="MsoNormal">Since this ctl file is generated by grads we tought you guys could help.<o:p></o:p></p>
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<p class="MsoNormal"><o:p> </o:p></p>
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<p class="MsoNormal">Do you know why the longitude is starting at -360?<o:p></o:p></p>
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<p class="MsoNormal"><o:p> </o:p></p>
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<p class="MsoNormal">Thanks in advance!<o:p></o:p></p>
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<p class="MsoNormal"><o:p> </o:p></p>
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<p class="MsoNormal">Raphael Ranieri<o:p></o:p></p>
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