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        MAP\XY_MAP [TableName] [/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 XY table name is giv-
    en  as  input.  If its extension is omitted, ".bat" table is selected if
    present, else ".tab" table is assumed. If the XY table name is  omitted,
    the  name  used  at the last command call is reused. The output LMV cube
    (.lmv) and the WEI image (.wei) share the XY table name prefix.

    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 2018-10-15