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Specify a list of keys to index on. By default the input files are indexed on the MARS keys. For each key a string (key:s) or a double (key:d) or an integer (key:i) type can be requested.
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Version.
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Message type. T->GTS, B->BUFR, M->METAR (Experimental),A->Any (Experimental). The input file is interpreted according to the message type.
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