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        MAP\XY_MAP [TableName [CubeName]] [/NOGRID] [/TYPE LMV|VLM|...]

    Build  an LMV spectra cube and an associated weight image from an XY ta-
    ble (usually produced with the command TABLE).

    The input XY table name is given as first input.  If  its  extension  is
    omitted,  ".bat"  table is selected if present, else ".tab" table is as-
    sumed. If the XY table name is omitted, the name used at the  last  com-
    mand call is reused.
    The  output cube (.lmv, .vlm, ...) and the weight image (.wei) names are
    given as second input. If omitted, they share their names  with  the  XY
    table one.

    By  default,  data  is gridded with a convolution (general case), unless
    /NOGRID option is invoked (typically when the data is already  regularly
    placed). See subtopic for details.

    By default, the spatial grid of the LMV cube will be large enough to use
    all the spectra of the XY table. The pixel size will ensure Nyquist sam-
    pling (i.e. at least 2 pixels per beam). The grid position reference and
    position angle will be taken from the XY table header.  The  convolution
    kernel is a Gaussian of size one-third the telescope beamwidth, the con-
    volution being computed on a limited support (large enough to ensure ex-
    cellent  accuracy). The gridding can be customized with a set of parame-
    ters, see subtopic TUNING for details.

    For large datasets, XY_MAP will process the data by slices of  channels.
    This introduces reading, computing, and writing overheads, but there are
    ways to limit those. See subtopic MEMORY for details.

    Note that the output LMV cube can be then  analysed  with  the  standard
    GreG  image tools like GO VIEW. However, it is also possible to reimport
    the cube in Class as a set of spectra thanks to the command  ANALYSE\LMV
    (see HELP for details).


Gildas manager 2020-10-13