MERIS Level 1 Radiometric Processor - Command Line Description

Processor Description

Since the MERIS Radiometric Correction processor makes use of the SNAP graph processing framework, it can be used also as a command line tool. The graph processing is invoked by the command

${OPTTBX-INSTALL-DIR}/bin/gpt

To obtain general help on the graph processing, use the command

${OPTTBX-INSTALL-DIR}/bin/gpt -h

Specific help on the MERIS Radiometry Correction processor, can be obtained with

${OPTTBX-INSTALL-DIR}/bin/gpt -h Meris.CorrectRadiometry

In this case, information on the usage and a list of all available parameters are given.

If MERIS N1 products shall be written as output result a graph xml file has to be created. This xml file should concatenate the Meris.CorrectRadiometry operator and the Meris.N1Patcher operator. A possible graph xml file would look like the following. For demonstration purpose only the necessary parameter have been set.


    <graph id="RadiometryCorrectionN1">
        <version>1.0</version>
        <node id="radiometry">
            <operator>Meris.CorrectRadiometry</operator>
            <sources>
                <source>${n1Product}</source>
            </sources>

        </node>
        <node id="n1Writer">
            <operator>Meris.N1Patcher</operator>
            <sources>
                <n1>${n1Product}</n1>
                <input>radiometry</input>
            </sources>
            <parameters>
                <patchedFile>${n1TargetFile}</patchedFile>
            </parameters>
        </node>
    </graph>

This graph can be invoked by the following call on the command line:

  gpt <graph-file.xml> -Pn1TargetFile=<path-to-target-file> -Sn1Product=<path-to-source-file>