<html><head><style type='text/css'>p { margin: 0; }</style></head><body><div style='font-family: times new roman,new york,times,serif; font-size: 12pt; color: #000000'>Hi,<br><br>maybe your file has some problem in its last line of 560 bytes (corrupt data or lacking of data).<br>However, the problem could be in your procedure in taking the header away.<br>Your .ctl says that the image has 560 x 560 pixels of 1 byte each = 313600 bytes.<br>Location 313040 + 560 bytes = 313600 bytes, which indicates that GrADS was looking for the last 560 bytes (in relation to what your .ctl says) when the problem was detected.<br>If the .ctl works well with the IR image, it should work with the VIS images as well, which is something (kind of) strange if not.<br>Please, check if the VIS images have the same sizes that the IR images (313600 bytes in size, I guess) in the disc system. They should have.<br>Other test to try:<br>Instead of taking away (manually I suppose) the header of files, you can use this optional entry for your control file:<br>THEADER lenght_of_header<br>Doing this way, the header will automatically be skipped by GrADS.<br><br>Hope this helps or gives you some other idea to solve the problem,<br>Ricardo<br><br><hr id="zwchr"><blockquote style="border-left:2px solid rgb(16, 16, 255);margin-left:5px;padding-left:5px;color:#000;font-weight:normal;font-style:normal;text-decoration:none;font-family:Helvetica,Arial,sans-serif;font-size:12pt;"><b>De: </b>"Charles Tai" <zhong2101@gmail.com><br><b>Para: </b>gradsusr@gradsusr.org<br><b>Enviadas: </b>Sexta-feira, 15 de Novembro de 2013 2:47:39<br><b>Assunto: </b>[gradsusr] An error occurred while displaying satellite data<br><br><div dir="ltr">Dear GrADS users,<div>I'm trying to display satellite images of pgm format with GrADS.</div><div>These are what I did for that:</div><div>1. Take away the header of pgm file to prevent of the geographic shifting.</div>
<div>2. Write a description file (as the attached file) for GrADS.</div><div>These procedures performed well in displaying IR images, but did not work for vis images.</div><div>Here are the error message I got from it:</div>
<div>---------------------------------------------------------------------</div><div>Low Level I/O Error: Read error on data file </div><div> Data file name = ./sat/MTS212%m2%d2%h2VIS.pgm </div><div> Error reading 560 bytes at location 313040 </div>
<div>Data Request Error: Error for variable 'mtsat'</div><div> Error ocurred at column 1</div><div>DISPLAY error: Invalid expression </div><div> Expression = mtsat</div><div>----------------------------------------------------------------------</div>
<div>Does anyone have similar experiences like this?</div><div>I would appreciate any help. </div></div>
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