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<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"><html><head><title>MSG -- Meteosat Second Generation</title></head><body style="background-color: rgb(255, 255, 255);"><h1>MSG -- Meteosat Second Generation<br></h1>This driver implemets reading support for Meteosat SecondGeneration files. These are files with names likeH-000-MSG1__-MSG1________-HRV______-000007___-200405311115-C_, commonlydistributed into a folder structure with dates (e.g. 2004\05\31 for thefile mentioned).<br><br>The MSG files are wavelet-compressed. A decompression library licensed from Eumetsat is needed ("<font face="Arial,Helvetica"><font size="-1"><font color="#000000">WaveletTransform Software</font></font></font>" -<a class="moz-txt-link-freetext" href="http://www.eumetsat.int/en/dps/helpdesk/tools.html#wavelet">http://www.eumetsat.int/en/dps/helpdesk/tools.html#wavelet</a>). Under some restrictions, this library is free to download.<br><br>Part of the source of the file xrithdr_extr.c from XRIT2PIC is used toparse MSG headers. This source is licensed under the terms of the GNUGeneral Public License as published by the Free Software Foundation.<br><br>This driver is not "enabled" by default. See "Build Instructions" on how to include this driver in your GDAL library.<br><h2>Build Instructions<br></h2>Download the Eumetsat library for wavelet decompression. This is afilenamed PublicDecompWT.zip. Extract the content in a subdirectory withthe same name (under frmts/msg). If you are building with Visual Studio6.0, extract the.vc makefiles for the PublicDecompWT from the filePublicDecompWTMakefiles.zip. If you build using the GNUMakefile and youfind that some adjustments are needed in the makefile and/or the msgsource files, please "commit" them. The Eumetsat library promises to be"platform indepentent", but as we are working with Microsoft Windowsand Visual Studio 6.0, we did not have the facilities to check if therest of the msg driver is. Furthermore, apply steps 4 to 7 from the <a href="http://www.gdal.org/gdal_drivertut.html">GDAL Driver Implementation Tutorial</a>, section "Adding Driver to GDAL Tree".<br><h2>Specification of Source Dataset<br></h2>It is possible to select individual files for opening. In this case,the driver will gather the files that correspond to the other strips ofthe same image, and correctly compose the image.<br>Example with gdal_translate.exe:<br>gdal_translateC:\hrit_a\2004\05\31\H-000-MSG1__-MSG1________-HRV______-000008___-200405311115-C_c:\output\myimage.tif<br><br>It is also possible to use the following syntax for opening the MSG files:<br><ul> <li>MSG(source_folder,timestamp,(channel,channel,...,channel),use_root_folder,data_conversion,nr_cycles,step)</li> <ul> <li>source_folder: a path to a folder structure that contains the files</li> <li>timestamp: 12 digits representing a date/time that identifies the 114 files of the 12 images of that time, e.g. 200501181200</li> <li>channel: a number between 1 and 12, representing each of the 12available channels. When only specifying one channel, the brackets areoptional.</li> <li>use_root_folder: Y to indicate that the files reside directlyinto the source_folder specified. N to indicate that the files residein date structured folders: source_folder/YYYY/MM/DD</li> <li>data_conversion:</li> <ul> <li>N to keep the original 10 bits DN values. The result is UInt16.</li> <li>B to convert to 8 bits (handy for GIF and JPEG images). The result is Byte.</li> <li>R to perform radiometric calibration and get the result in mW/m2/sr/(cm-1)-1. The result is Float32.</li> <li>L to perform radiometric calibration and get the result in W/m2/sr/um. The result is Float32.</li> <li>Tto get the reflectance for the visible bands (1, 2, 3 and 12) and thetemprature in degrees Kelvin for the infrared bands (all other bands).The result is Float32.</li> </ul> <li>nr_cycles: a number that indicates the number of consecutivecycles to be included in the same file (time series). These areappended as additional bands.</li> <li>step: a number that indicates what is the stepsize whenmultiple cycles are chosen. E.g. every 15 minutes: step = 1, every 30minutes: step = 2 etc. Note that the cycles are exactly 15 minutesapart, so you can not get images from times in-between (the step is aninteger).</li> </ul></ul>Examples with gdal_translate.exe:<br><br>Example call to fetch an MSG image of 200501181200 with bands 1, 2 and 3 in IMG format:<br>gdal_translate -of HFA MSG(\\pc2133-24002\RawData\,200501181200,(1,2,3),N,N,1,1) d:\output\outfile.img<br><br>In JPG format, and converting the 10 bits image to 8 bits by dividing all values by 4:<br>gdal_translate -of JPEG MSG(\\pc2133-24002\RawData\,200501181200,(1,2,3),N,B,1,1) d:\output\outfile.jpg<br><br>The same, but reordering the bands in the JPEG image to resemble RGB:<br>gdal_translate -of JPEG MSG(\\pc2133-24002\RawData\,200501181200,(3,2,1),N,B,1,1) d:\output\outfile.jpg<br><br>Geotiff output, only band 2, original 10 bits values:<br>gdal_translate -of GTiff MSG(\\pc2133-24002\RawData\,200501181200,2,N,N,1,1) d:\output\outfile.tif<br><br>Band 12:<br>gdal_translate -of GTiff MSG(\\pc2133-24002\RawData\,200501181200,12,N,N,1,1) d:\output\outfile.tif<br><br>The same band 12 with radiometric calibration in mW/m2/sr/(cm-1)-1:<br>gdal_translate -of GTiff MSG(\\pc2133-24002\RawData\,200501181200,12,N,R,1,1) d:\output\outfile.tif<br><br>Retrieve data from c:\hrit-data\2005\01\18 instead of \\pc2133-24002\RawData\... :<br>gdal_translate -of GTiff MSG(c:\hrit-data\2005\01\18,200501181200,12,Y,R,1,1) d:\output\outfile.tif<br><br>Another option to do the same (note the difference in the Y and the N for the “use_root_folder” parameter:<br>gdal_translate -of GTiff MSG(c:\hrit-data\,200501181200,12,N,R,1,1) d:\output\outfile.tif<br><br>Without radiometric calibration, but for 10 consecutive cycles (thus from 1200 to 1415):<br>gdal_translate -of GTiff MSG(c:\hrit-data\,200501181200,12,N,N,10,1) d:\output\outfile.tif<br><br>10 cycles, but every hour (thus from 1200 to 2100):<br>gdal_translate -of GTiff MSG(c:\hrit-data\,200501181200,12,N,N,10,4) d:\output\outfile.tif<br><br>10 cycles, every hour, and bands 3, 2 and 1:<br>gdal_translate -of GTiff MSG(c:\hrit-data\,200501181200,(3,2,1),N,N,10,4) d:\output\outfile.tif<br><h2>Georeference and Projection<br></h2>The images are using the Geostationary Satellite View projection. MostGIS packages don't recognize this projection (we only know of ILWISthat does have this projection), but gdalwarp.exe can be used tore-project the images.<br><p>See Also:</p><p></p><ul><li> Implemented as <tt>gdal/frmts/msg/msgdataset.cpp</tt>.<p></p></li><li><a href="http://www.eumetsat.int">http://www.eumetsat.int</a><p></p></li></ul></body></html>⌨️ 快捷键说明
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