; DO3DIMAG
;---------------------------------------------------------------
;! specifies whether uvw's are reprojected to each field center
;# ADVERB IMAGING
;-----------------------------------------------------------------------
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DO3DIMAG  LLLLLLLLLLLLUUUUUUUUUUUU CCCCCCCCCCCCCCCCCCCCCCCCCCCCC
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DO3DIMAG
Type: Adverb  (scalar)
Use:  To specify whether a data set is imaged with "3-dimensional"
      techniques.  True means to make each facet tangent to the
      celestial sphere at its center.  False means to make each facet
      tangent to the celestial sphere at the phase-stopping
      coordinate even when that point is not within the facet.
      Beginning about May 1, 2009, the code for false is implemented
      by a technique which has been described as "u-v plane faceting"
      which corrects for 3D effects rather better than the previous
      code.  True seems still to produce better images but the
      difference is now marginal.  The cost to compute either true or
      false imaging is about the same.

Null value: 0
      Taken to mean false.

Tasks:
    IMAGR........Fourier transforms and Cleans uv data with wide-field,
                 interactive TV, and data weighting options.  DO3DIMAG
                 > 0 selects the tangent form of faceting.
    SCIMG........Full-featured imaging plus self-calibration loop with
                 editing.  DO3DIMAG is used the same as in IMAGR.
    UVCON........Generate sample UV coverage given a user defined array
                 layout.  DO3DIMAG > 0 sas to use the W term in
                 calculating visibilities when doing DFT of Clean
                 components.
"Verbs":
    OBITIMAG.....Access to OBIT task Imager without self-cal or peeling.
                 DO3DIMAG is used as in IMAGR,
    OBITPEEL.....Access to OBIT task Imager with self-cal and peeling.
                 DO3DIMAG is used as in IMAGR,
    OBITSCAL.....Access to OBIT task Imager with self-cal, NOT peeling.
                 DO3DIMAG is used as in IMAGR,
Procedures:
    LINIMAGE.....Build image cube from multi-IF data set.  DO3DIMAG is
                 passed to IMAGR.
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